The 3 bits that came with my FAT wrench have the following markings on them:

874-877

449-509

192-418

What do these numbers mean and is it possible to relate them to the SAE system?

874-877 - 3/32 allen bit
449-509 7/64 allen bit
192-418 5/32 allen bit

source
http://gunsumerreports.com/rev..._mount_kit_combo.php

Wow, good find! Do you know if those numbers are internal Wheeler numbers or from some external numbering system?

I think its internal numbers ... no clue, honestly

I'm sure they are outsourced

Well I tried to track down Wheeler Engineering and learned they are part of a larger concern, Battenfeld Technologies. I asked my question of them and received this response:

"the numbers on our bits are our part numbers and do not relate to any other system".

Anyway, after a good bit of searching (Home Depot had nothing) I found a set of hex bits that fit a 1/4" drive and ordered them -- and they have the SAE sizes written on them!

the bigger system they are part of is
www.midwayusa.com btw

I think if you dig a little deeper, you'll find that Wheeler is owned by Battenfield Technologies, which was recently purchased by Smith & Wesson.

wow! that is new news --
http://www.prnewswire.com/news...s-inc-300001457.html