Swarovski SOC Stay-On Case BTX Eyepiece ModuleThe Swarovski SOC Stay On Case BTX Eyepiece Module protects the BTX Eyepiece Module from impact damage, and is an absolute necessity for keeping it safe. The case remains on the eyepiece module both while in use and while not in use, as some of the most harmful damage to spotting scopes if often sustained when your tripod topples over.