This is a 12" length overall heater. It is a 2" tube bundal of high density cross tubular flow design. It is fitted with 3/4" hose barb ends for the coolant and 3/8" female pipe thread oil fittings. I find this sized unit perfect for 4 or 5 cylendar applications. The design considers coolant flow rates thew hose size and from water pump capacity. The oil side of the unit is balfold to match the surface area to the oil flow rate of the engine. This unit is a highly effective maximum heat transfer unit, not a fuel warmer. It is heavily built, buy an industrial heat exchanger manufacture to my spects. It is made of copper, rated for 150PSI and salt water service. In a five cylendar this unit can heat 50*F oil to 150*F at hiway speeds with no other heat when it is 50*F out. This in-line heater is the main source of conversion heat I use. The electric heater I use to preheat and start the system and in cold conditions. Tank heat is only for pumpability to draw the oil foward, but the in-line heater needs to be the work horse of the system. This is a great supply of free energy to your SVO. My price includes UPS ground, In the continental states, shipping and handling charge. Florida sales tax will be added to to that. our 15" heat exchanger I use for 6 cylendar engines or up north is on back order. We also have a 18"X3" for v-8 engines that is on back order :) Sorry!