Glidecam Smooth Shooter Support Arm and Vest for use with 2000 Pro, 4000 Pro, HD-2000 or HD-4000 The Support Arm can be setup and used in either a One-Spring Mode, or a Two-Spring Mode In the One-Spring Mode, the Support Arm can hold a total combined camera and hand-held stabilizer weight of 9 pounds In the Two-Spring Mode, the Support Arm can hold a total combined camera and hand-held stabilizer weight of 18 pounds.