What sizes are the most common? ... Found the internet! 1. Common torx sizes. Close. 1. Posted by 4 months ago. Common torx sizes. I've got 3 slots left in my impact bit case and I want to put some torx bits in there. What sizes are the most common? I'm in New Zealand if that means anything. I was thinking t25, t15 and t50?. 2021. 2. 19. · 1. Gmundcars.com Torx bit sockets Internal torx bolt can be found in automotive industry and computer system. Torx bit (or External Torx/Male Torx) sockets are designed to fit and turn fasteners with an internal Torx head. The sizes of Torx bit sockets are described using the letter T followed by a number, ranging between T1(smallest) and T100.