363846 Piston ring set, for Lister Petter AC1 Series 2 and the AD1 engines.363846 Piston ring set, used on the AC1 and the AD1 engines. This will be item number 13 in the Lister Petter drawing. NSN The AC AB1 AD1 engines were used in a wide range of equipment, the AC1 version was used in the following equipment Amida series DLB Detour Lite, Compac P24 33 walk behind compactor, Ampac P33 24 walk behind compactor. US Military BT400 NEX D, BT 400 46 Ground support portable heater, this unit was made by Aerotech Herman Nelson