In theory, Ultrasabers blades and blade plugs should work with ANY lightsaber hilt designed for a 1 inch diameter blade. Ultrasabers blades and blade plugs are listed as measuring 1 inch in diameter, after all. In reality, some Ultrasabers blades and blade plugs don’t fit due to a slight variation in diameter. Ultrasabers quality control appears to allow a wider range of variation from blade to blade and blade plug to blade plug than some other custom saber companies. That means some Ultrasabers blades may fit smoothly into a lightsaber hilt socket while other may not.
If the lightsaber blade doesn’t fit into a hilt’s blade socket, DO NOT try to force the blade to fit. You could damage the blade, or worse yet, the blade could get stuck in the hilt. The same goes for blade plugs.
If the lightsaber blade or blade plug doesn’t fit in the lightsaber hilt, some lightsaber enthusiasts will decrease the blade diameter by sanding down the the blade tang (i.e. the section of the blade that is inserted into the hilt’s blade socket) until the blade fits.