I first bought these when my digital tire inflator for EPAuto 12V DC Portable Air Compressor started dying and pulling air instead of pumping it. maybe a problem with the nozzle, but after that it didn't work, I threw it away. When attaching this block, it fit so poorly that air escaped from the attachment point. but no air came out of the tube. then i tried it on my goodyear i8000 direct drive 120v tire inflator but it wouldn't blow air with it. Too bad because it goes perfectly with this pump, nice and reliable. and how easy it was to securely attach them to bicycle tire valve cores. and finally the new pump I took with me for the trip - JACO SmartPro 2.0 AC/DC Digital Tire Inflator - Advanced Portable Air Compressor Pump - this cartridge is airtight. Great for a bike tire, but it doesn't deflate, so there's no point in buying one. spend hard earned money.