If you've bought a used Dell dock and the only model number you can find is "K20A001", you haven't actually identified it. That code is a regulatory type shared by six different WD19 docks, and they don't all do the same job. Some pass more power than others, one comes with a second cable that does far less than people assume, and mixing them up means ordering the wrong power supply or expecting features that aren't there. This guide shows you how to tell them apart by looking at the cable coming out of the dock, not the sticker.
Quick answer
Dell WD19 docks are told apart by their cable, not their label. One captive USB-C cable means WD19 or WD19S. A cable marked Thunderbolt, plus an extra Thunderbolt port on the back, means WD19TB or WD19TBS. Two captive USB-C cables means WD19DC or WD19DCS, where only the primary cable carries data and video and the second cable is a 15W power-only cable for charging a phone or tablet2. No 3.5mm audio jack on the front means it's an "S" variant of whichever family you've identified.
Why the label doesn't help
Dell's regulatory compliance ID, printed on the base of the dock, covers a family of products rather than one specific model. K20A001 is the one you'll see most often on used WD19 stock, and it's used across the standard WD19, the audio-free WD19S, the Thunderbolt WD19TB/WD19TBS, and the dual-cable WD19DC/WD19DCS. Trying to order a power supply or check specs against "K20A001" alone will send you to the wrong page. The cable and rear ports are what actually distinguish them.
If you're new to docks generally, our docking station buying guide covers the different connection types before you get into brand-specific variants like this one.
Identify your dock in three checks
- Count the captive cables coming out of the dock. One means WD19 or WD19S. Two means WD19DC or WD19DCS.
- Look at the cable and rear ports for Thunderbolt. A cable printed with the Thunderbolt logo, combined with an extra Thunderbolt port on the back of the dock, means WD19TB or WD19TBS.
- Check the front for a 3.5mm headphone/mic jack. No jack means you have an "S" variant of whatever family you identified in steps 1 and 2. With a jack, it's the standard version.
Variant comparison
| Variant | Cable(s) | Distinguishing feature | Audio jack |
|---|---|---|---|
| WD19 | One USB-C | Standard USB-C host connection | Yes |
| WD19S | One USB-C | Same as WD19 | No |
| WD19TB | Thunderbolt-marked cable | Extra rear Thunderbolt port | Yes |
| WD19TBS | Thunderbolt-marked cable | Extra rear Thunderbolt port | No |
| WD19DC | Two captive USB-C cables | Second cable is 15W power-only, for phone/tablet charging | Yes |
| WD19DCS | Two captive USB-C cables | Second cable is 15W power-only, for phone/tablet charging | No |
What we see in our workshop
The single biggest problem with used WD19 docks isn't a fault, it's a missing cable. On the WD19DC and WD19DCS, only the primary cable connects the dock to your laptop for data, video and the dock's main power delivery. The second cable is a 15W power-only connection meant for topping up a phone or tablet while you work, not a second data or video link2. If a used WD19DC is missing its second cable, the dock still works fully as a laptop dock, you simply lose the convenience of that extra phone-charging port. This is the same pattern we see across used docks generally: the label rarely tells the full story, and missing accessories are more common than actual hardware faults.
Power delivery: check the adapter, not just the dock
Power delivery on the WD19 family depends on which power adapter shipped with the dock, and whether your laptop is a Dell. Dell's own specifications confirm the 180W adapter delivers 130W to a Dell laptop and 90W (USB PD 3.0) to a non-Dell laptop1. We could not independently confirm the exact wattage Dell's 130W adapter delivers to a Dell laptop from the rendered specification table, so we've left that figure out rather than guess. If you're relying on a specific wattage, check the model's exact adapter and confirm against Dell's own docking specifications page for that dock before you buy.
The WD19DC and WD19DCS are a separate case. With their own 240W adapter and both cables connected, Dell rates them for up to 210W to supported Dell Precision systems2. That is a materially higher figure than the WD19/WD19S/WD19TB range and only applies to the dual-cable docks on supported Precision hardware, so don't assume it carries over to a standard WD19 or to a non-Precision laptop.
For comparison, other docks handle this differently. The Kensington SD4700P, for example, uses a fixed 135W power supply and passes up to 60W to the laptop regardless of brand3, a simpler figure than the WD19 family's adapter-dependent numbers, but lower overall.
What to skip
- A used WD19 with no power adapter at all. Without knowing which adapter it originally shipped with, you can't confirm what it delivers to your laptop, and a mismatched generic supply may not deliver full power.
- Assuming "TB" means faster charging. Thunderbolt on the WD19TB adds a Thunderbolt pass-through port for daisy-chaining; it doesn't change power delivery figures.
- Expecting the WD19DC's second cable to carry video or a second laptop connection. It's a 15W power-only cable for a phone or tablet, not a second data or video link.
Buying refurbished from Buyer Area
When we list a used dock, we identify it by its actual variant rather than the regulatory code on the label, and we tell you plainly whether the power supply and host cable are included. Every dock comes with a 12-month warranty, 30-day returns and free UK delivery, on the same terms explained on our refurbished grades page. If you already own a WD19 dock and aren't sure which variant it is, send us a photo of the cable and rear ports and we'll help you identify it before you buy anything to go with it.
refurbished Windows laptops to pair with a dock
FAQ
How do I tell a Dell WD19 from a WD19S?
Both use a single captive USB-C cable and look almost identical. The difference is the front panel: the WD19 has a 3.5mm headphone/mic jack, the WD19S doesn't. Everything else, including power delivery, is the same.
Does the WD19TB work with a non-Thunderbolt laptop?
It can connect over USB-C to a non-Thunderbolt laptop, but you'll lose Thunderbolt-specific features like the daisy-chain port. Check Dell's own specifications for the exact power delivery figure for your adapter and laptop brand, as this varies across the range.
Why does my WD19DC have two cables?
Only the primary cable connects your laptop for data, video and the dock's main power. The second cable is a 15W power-only connection for charging a phone or tablet while you work, not a second data or video link. With both cables connected and the dock's own 240W adapter, Dell rates the WD19DC and WD19DCS for up to 210W on supported Dell Precision systems.
Will a WD19 dock charge my MacBook?
It will charge a MacBook over USB-C, but the exact wattage depends on the specific WD19 variant and adapter, and Dell's higher power figures are aimed at Dell laptops. Check your dock's adapter and Dell's own docking specification page for that model, and compare it against your MacBook's original charger wattage.
Sources
- Dell, "Dell Docking Station WD19 User Guide: Docking specifications". https://www.dell.com/support/manuals/en-uk/dell-wd19-130w-dock/wd19_userguide/docking-specifications?guid=guid-cd615eef-5015-4931-bf9b-e19f9cf50c4d&lang=en-us (checked 2026-09-17) ↩
- Dell, "Dell WD19DC Dock User Guide: Quick setup of hardware". https://www.dell.com/support/manuals/en-us/dell-wd19dc-dock/wd19_dc_userguide/quick-setup-of-hardware?guid=guid-7ff5dcdc-e491-44a0-a967-643a9dbd23e9&lang=en-us (checked 2026-09-17) ↩
- Kensington, "SD4700P USB-C & USB-A 5Gbps Dual 2K Hybrid Dock". https://www.kensington.com/p/products/device-docking-connectivity-products/laptop-docks-usb-accessories/sd4700p-usb-c-usb-a-5gbps-dual-2k-hybrid-dock-up-to-60w-pd-dp-hdmi-windowsmacos/ (checked 2026-09-17) ↩