The Hour Glass heat exchanger cooling system provides maximum cooling for your TRX 3.3 engine. The heat exchanger tubes double the surface area of the head and allow more efficient cooling of the engine. The tubes can be added and removed to increase and reduce the cooling effectiveness of the head. The tubes are held in place by the top mounting flange plate with five mounting screws. This top plate allows easy access to the head bolts but keeps head bolts captive in the head to ensure the screws are never lost. This head and top plate are micro-polished with anodized blue tubes.  Note;  Some glow plug wrenches and glow ignitors do not fit with head.  We offer the glow wrench under tools section.