Bought a Skan chronograph years ago where you shoot through a 2inch hole through the middle of the machine, being 30 years old the electronics are give and take between shots, most probably the sensors need cleaning. I was thinking of buying a new chrono and was looking at the cheapo ones on Fleaybay from China, there seems to be two types, one where you shoot through a hole like the skan and the other F1 type with Y shape rods you shoot through. Are they any good or just junk. I don't want a chrono where you bolt it to the end of the guns muzzle and have to use a phone app to use it.