to alcohol (for cleaning), and an aesthetically pleasing appearance. Another motivating factor for Tandem's choosing RTP's compound was the material's ability to be formed into large, complex shapes without distortion. The pump itself features a large, flat, stainless-steel spring that operates similarly to those found in mechanical watches: as the housing is opened, the spring retracts to its original position. The stored force then dispenses up to four intravenous solutions from the bag. If the system is dropped, RTP's compound offers protection with unnotched Izod impact strength at 3.18 mm of 801 J/m. The compound's flexural strength is 26,000 psi; its tensile strength is 18,000 psi.