BudsGunShop.com - Whats the difference?

Finish, grips, sights and number of magazines.. The sale models very often will come with 3 magazines & night sights while the standard models usually come with just 1 magazine.

The SIG 938 has many variants that are mostly cosmetic. Different finishes, grips and sights. All are the same basic platform.

It's impossible to answer this question without further information/links to the other models you are asking about.