Float Equipment Differential Fill-Up Shoes Model No.: CT-CDFS The differential fill-up shoe and differential fill-up collar allow optimum, metered filling of the casing, while it is being run in the hole. Advantages: Reduces casing running time. Lowers surge pressures on formations. Operational Benefits: Minimizes the possibility of sticking. The Differential fill-up equipment can be converted from the fill-up to the backpressure mode at any time during the casing run by dropping the weighted ball furnished with each piece. Notice: JavaScript is required for this content.