I was puzzled at that too - perhaps it should have been 7/8 - but it says 5/8 in two places

Product Description No. 99 says

Five- level 5/8" or 11/16" width fully perforated
paper tape output (Tape notching
on 0 and 6th. level punch pins)

Punch block has eight pins plus feed hole
pin. Tape guide and die plate slot permit
use of 5/8" or 11/16" tape only.