Ultra-Cure is a very high performance clear cyanoacrylate that has a viscosity (thickness) in-between that of Insta-Cure Super Thin and Insta-Cure+ Gap Filling Medium. It is ideal for the mounting of rubber tires onto R/C car wheels. ULTRA-CURE can be used in many other applications that require a slightly thicker thin CA and will bond virtually everything. It is not foam-safe, however.