Shark 1085fp Belt Set for Shark Infinity Models NV30 and NV31 Shark Infinity 1085fp belt set. Package of (2) belts. The 1085fp belt set includes, (1) large drive belt and (1) small tension belt. Fits all Shark Infinity NV30 and NV31 models which were manufactured before the 37th week of 2006 (Date Code 37/06) If you have a model NV30 or NV31 manufactured after 37/06 then you will need the 1102fp belt set. Replace belts every 3 to 6 months for optimum performance.