The Adjustable, Universal Rear Anti Tippers with Wheels in black by Drive Medical can be used on most leading manufacturers wheelchairs. The unique, spring loaded, flip lock mechanism easily flips up and down for traversing curbs safely and securely. A universal spacing sleeve can be added or removed to accommodate a secure fit with Drive Medical Viper Plus Wheelchair. Unique Spring Loaded Flip-Lock mechanism easily flips up and down for traversing curbs|Universal spacing sleeve can be added or removed to accommodate a secure fit with the Viper Plus|Provides stability|Easy to install