You don't have to be a master modeller to add the realism of functioning retracts to your Model. E-Flite's completely self contained retract system doesn't require an air tank, complex linkages or even an extra servo. You simply bolt it into place and plug it into the receiver. A specially designed Y-harness is included that lets you use a single receiver channel to control all retract units. This is the plug in retract solution you've been waiting for. SpecificationsApplication Aircraft 25-46 SizeMain Gear 2.8 oz (79.5g) eachOperating Voltage Range 4.8v-7.4v Aircraft Weight 5.00-9.50lb (2.25-4.30kg) Retract Unit specsLength 71 1/2mmOverall Width 40mmBody Width 14mmHeight 25mmLeg Length 193mmWeight 82 grams