ISO-Lateral Shoulder Press.

The shoulders press. The back gets a rest.

Shoulder press with a bar or dumbbells requires the upper body to hold itself in place while the shoulders work, and the lower back usually arches a little more with every rep. The back support here takes that job, so you can press heavy without something else giving way first. The levers are independent, so each side gets its own load and its own range of motion instead of following the stronger one. Olympic plates (Ø50 mm) on pegs at both ends, 253 kg empty frame, 2130 × 1210 mm floor space and 2100 mm height. The press stops when the shoulders are empty. Not before.