This is a Pack of 10 Groz-Beckert BlindStitch Sewing Machine Needles.

LWX5T will fit industrial blindstitch machines from Consew, Columbia, US Blindstitch, Rex and many more.

Needle system : LWX5T, 251EL

These needles also cross to these different needle systems : 

251EL, 251LG, 300, 29BNL, 29CB, 29-C-300LG, LWX5T, SY7425

A needle system is a group of needles made to fit specific sewing machines. All needles in a system are of the same length and shank size, but are of various diameters. Lower size numbers are narrower or thinner needles used for lighter materials. Higher size numbers indicate a needle of thicker diameter, used for heavier materials. Match your needle system to your machine, then the size of the needle to the product you are sewing.