HF leak down tester

I bought on of the HF units and it wasn't accurate at all. Had it on sale and I had a 20% off coupon so it was real cheap so I should have known. The problem was the gauges were junk. I have a tool store near me that gets closeout deals on all sorts of stuff and they had good quality gauges for $5 each and before I installed them I tested each and both read within 1 psi of each other at 100 psi so I installed them and it's accurate now.