Arena Powerfin - Short Training Fins Black / 37-38 (6-7) The Unisex Arena Powerfin Training FIns are ideal for fitness swimmers and competitive swimmers. They are designed to work power and improve the beatings of the legs. The durable soft silicone material offers maximum comfort and reduces the risk of bulbs. Without PVC. 100% long-lasting silicone Increased comfort for a reduction in bulb risk Short fins for power training Powerfins Arena Fins are designed to make your workout more efficient by allowing you to work your technique. The Powerfin is ideal for power training. Designed with a diamond tip and a comfortable closed heel. Made of silicone that prevents bulbs.