The al ko 40bck comprises the energy flex mt36li base unit and bca36li brushcutter attachment. They are part of the alko energyflex 36v multi tool range and the mt36 li base unit can be used with all the attachments. Supplied without a battery, the 40bck can be fitted with either the 4ah or 5ah energy flex lithium ion batteries. If used with a 4ah battery the bck40 has a running time of up to 25 minutes. The working time will vary depending on the length and thickness of the material being cut.the bca 36li attachment has an auto bump feed head and metal blade. The head releases fresh line when it is 'bumped' on the ground. battery and charger not included.specificationsbattery type required 36v energy flex not includedcharge time 1.5 hoursrunning time up to 25 minutesshaft type splittrimmer head auto bump feedblade metal 3 tooth, 23cm diameterweight without battery 2.8kghandle type loopmanufacturer warranty 2 year homeowner