Acavallo Arena AluPlus 2.0 StirrupsSafety mechanism positioned on the top: prevents sand and dirt from delaying the arm opening action New aluminum opening arm The locking and release mechanism is one centimeter higher than the bench, thus preventing the foot from accidentally slipping out of the stirrup. Long horizontal holes to prevent the accumulation of sand and dirt Five degree incline of the bench to ensure correct position Bench width 12. 5 cm Maximum arm opening: 105 mm Maximum