【660 LBS Load Capacity】PROIRON calf stretch board is fully steel-made, with a 2.5mm-thick engraved steel panel, a 2mm-thick square steel tube frame, and 10mm-thick solid round steel supports. It can hold up to 600 lbs, stronger than wooden fitness gear, avoiding cracking risks and ensuring safety even in high-intensity workouts. 【5-Angle Flexible Adjustment】：Calf stretcher slant board features 5 adjustable angles from 20° to 45°. The gentle angle suits daily relaxation, while inclined ones fit high-intensity training, especially for calf and hamstring exercises. Both beginners and pros can find the ideal angle. 【Thick and Comfortable Foam】：The ankle stretcher’s foot fixed tube is wrapped in 8mm-thick NBR foam, fitting the heel perfectly. It offers soft contact for prolonged stretching or repeated squats, no discomfort, letting you focus fully on training. 【Safety and Slip Resistance】The base of the steel stretch board features four soft rubber feet with a textured surface, ensuring secure grip and preventing displacement while protecting floors from wear and tear. 【Two Exercise Modes】The product's foam-padded steel tube is detachable. When installed, it functions as a calf stretcher slant board ; when detached, it serves as a squat rack incline bench, achieving dual functionality as both a calf stretcher slant board and squat rack incline bench. steel slant board calf stretch stretching board for calves calf stretcher slant board for calf stretching incline board for calf stretching exercise