The 12-REA, Sine Rodless Cylinder - Magnetically Coupled accelerates slowly at beginning stroke and decelerates at end stroke designed for working with delicate materials such as silicone wafers, magnetic disks or LCD substrates yet optimizing throughput with speeds of up to 300 mm/sec. The 12-REA features specially designed U-shaped cushion rings at the cylinder end caps to prevent hard stops. The corresponding sides of the piston head have special cushion packing to faciliate smooth acceleration at the start of stroke. It uses fluorine grease making it inert to temperature fluctuations, chemical exposure and various gases which will not cause cracking or swelling in synthetic rubbers or elastomers qualifying it for ISO Class 5 (Class 100) clean room rating. Please note the 12-REA must be used with an external guide to support the load.