I have a no-name clone of my-64, not 63 but looks identical, and I wouldn't trust any CAT ratings. The quality varies a lot for clones.
NOT AN INSTRUMENT FOR ELECTRICIANS.
Might be a nice instrument for hobby-level electronics, good enough for casual measurements in electronics at low voltage. Not trustworthy for mains power. On the inside doesn't look well either. Not very reliable in time. The rotary switch developed shoddy contact after a few years and now it sometimes show zero when there is voltage. This can be very dangerous when checking mains voltage. It usually starts to show correctly again if you wiggle the rotary selector, though that disqualifies it from any kind of use.
I am keeping mine only for the 10A DC range (because for 10A range my instrument has only a thick copper wire inside, it has no fusible protection), which is useful to measure short-circuit current in 1.2V NiMH batteries (for about one second or so), so to discern between good vs. useless rechargeables.