Tap Adapter Size: #2 (5/16″ & 3/4″). FUNCTIONS AS IT SHOULD. Tap Adapter: TC-820B 3/4(ANSI). NEW in original tube. NOT made in china. I have a number of different sizes and types of Tapping holders & quick change tap adapters. #1-#3 adapter sizes, English & metric, with & without clutch. If you need a different size please ask! Only large items over 40 Lbs. Or extremely fragile items will not be combined. If items are paid for individually no discount can be given. I will not mark merchandise values below value or mark items as “gifts” – US and International government regulations prohibit such practices. 5/16 & 3/4 adapter included.