I confirmed how accurate mine was by shooting it directly into a £450 SKAN chrono, both were in 1fps of each other over 20 shots. Not bad for a £40 toy.
I own one. It´s reliable as long as you have good batteries on it. One good feat with it is that it always takes the reading at the exact same point,every shot,every time. It´s a good device to keep with you at the range due its size. For really serious tune-up and for many shot strings there are far better devices though but it´ll get the job done, sure.
I used one for years, they are superb.
I confirmed how accurate mine was by shooting it directly into a £450 SKAN chrono, both were in 1fps of each other over 20 shots. Not bad for a £40 toy.
money well spent