6 Wheel Hoist Trolley with Rollers - Strut Trolley Assembly for Electric Hoist -

6 Wheel Hoist Trolley with Rollers - Strut Trolley Assembly for Electric Hoist - Fits 1-5/8" Wide and Taller Strut Channel - High Strength and Silent Operation. This trolley is specially designed to operate silently, with eight high-strength steel wheels that roll smoothly and efficiently along any 1-5/8" wide or taller strut channel.

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