As with all Chinese made fittings, the tolerances are not very good. I've found that to get a good seal that doesn't leak, you need to use teflon tape and pipe sealant together to prevent leakage. I usually wrap three layers of tape around the nipple and apply sealant to the tape and internal threads before assembling them. I have found this to stop leaks and have tested my fittings up to 120psi.
6 Pack Miahart Adjustable 304 Stainless Steel 4 Inch Hose Clamp Duct 91Mm-114Mm Worm Gear Pipe Clamp For Automotive, Mechanical Agriculture.
18 Review
12V Brass Solenoid Valve, 3/4" Electric Air Valve For Water, Air, Gas, Fuel And Oil - Normally Closed By Beduan
10 Review
Vacuum cleaner Dreame V9 Global, white
145 Review
DIGITEN DC 12V 1/4" Inlet Feed Water Solenoid Valve Quick Connect N/C Normally Closed No Water Pressure
14 Review