This is a detail upgrade set for a 1/72nd scale TOG 1 model. The model that this is desinged for is listed on shapeways and is found on this
link. The set gives you the details for the turret barrel, and the side sponson cannon and MG details. The sets are fully detailed with exterior rivet details and also there are some interior details too. The sponsons are designed to be friction fitted in pace so you don't loose the interior engine details that are found on the stock model. The set also supplies you with 2 main barrels for use as a spare.