ARRI K2.0049637 
The TRINITY Skater from ARRI provides an easier way to quickly balance your TRINITY 2 or TRINITY 1 stabilizer. Its 4-step process enables you to reduce setup and balancing time to a minimum. It begins with placing your rig horizontally on the Skater and then positioning batteries and other accessories to evenly distribute weight and balance the rig.
4-Step Balancing
The four-step TRINITY Skater process includes a two-step procedure that enables you to pre-balance your TRINITY 2 or TRINITY 1 lower sled/rig and tilt axis before your shoot without needing your camera attached.
The last two steps involve balancing the camera using 16 neutral positions and finalizing the overall balance.
Skater Design
After placing your TRINITY rig on the skater in a horizontal position, the skater acts as a precise instrument to measure the balance of batteries and accessories as they are added to the stabilizer sled. 
The sturdy skater base uses two wheels with ultralow friction ball bearings and includes two spare wheels.