It's a trade secret how I found this (otherwise known as being a persistent Google detective).

On the RockAuto website, select Tools and Universal Parts then look at fuel pressure testers or type W80595 in the part number search field. Click on Info for details.

I then did a bunch of Google searching to verify that the included adapter was for a Schrader valve. Schrader valves are commonly used in fuel injection systems and it seems are usually one size up from the Schrader valves used with tires.

https://www.rockauto.com/en/parts/performance+tool,W80595,fuel+injection+tester,1001027

I've used RockAuto for many years and never been disappointed with their selection, prices and delivery. You should always verify fitments using other reputable websites. There's no 1-800 support number to call, but I find their contact form is reasonably responsive if you clearly state your issues and don't expect them to be anything more than an order desk. If you want a knowledgeable 1-800 number to talk to and don't mind paying extra for a lifetime guarantee then it's hands down FCPEuro for our old Volvos.
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Dave -still with 940's, prev 740/240/140/120 You'd think I'd have learned by now