Chapter 18.104.22.168 of the ISSF pistol rules says to the discipline free pistol: "b) Hand covers for 50m Pistols are permitted, providing they do not cover the wrist."
Otherwise, rule no. 8.7.1 "Firing Position" applies to Free Pistol: "The athlete must stand free without any artificial or other support, with both feet and/or shoes completely within the firing point. The pistol must be held and fired with one (1) hand only. The wrist must be visibly free of support."