The Spencer Impact Attachment was developed for use with Thwing-Albert’s Elmendorf Tear Tester. It provides a convenient method for determining the impact resistance of plastic films and packaging materials under conditions that closely approximate the strain rates that the material is subject to in end-use applications. Extremely consistent, the Spencer Impact Attachment provides one of the most repeatable methods of testing impact resistance of plastic film. The air-operated clamping assembly automates the clamping mechanism to ensure an even higher level of accuracy. The Spencer Impact Attachment is a modification to the standard ProTear Elmendorf Tearing Tester and consists of a curved metal arm that is permanently attached to the pendulum and is fitted on the end with an interchangeable impact head that is available in various shapes and sizes. This allows different materials and tests to be performed with one machine. An O-ring Sample Clamp is mounted at the top of the clamp upright. The pendulum swings the impact head through the clamped specimen with sufficient force to puncture the sample, and the energy used is recorded.