Ball Transfer Units Category Shows Products by Series and Features. They are threaded Stud and Downward and Spring Load and Flange Mount as Ball Transfer Feasures. By Series, they are D Heavy Duty Series, CY Stamping Series, IA and IS series, IK and UK Series, KSF and KSH and KSM Series, LW Full Screw Housing Series, NL Nylon Series, SI and SD Series, SP Heavy Load Series. SYZ Machine also Accept a Customized Request, Send us email or Leave a Message about Your Special Request.