ame... my D adapters are a generic single cell spacer type.. my heavier draw tent fans are adapted to a 12v car battery...got a pretty good supply of D cells for the MagLights

freeballer...the Black Diamond has a third strap, with the battery pack in the rear...very solid, though it does weigh more than the cheaper 3 AAA single strap ones... so far, very comfortable, wore it when I was reclaiming a shallow well, for about 4 hours down in the well...I still have a couple of the older AAA Energizers with lithium stashed in the car