As the regulations regarding air travel with Lithium Ion batteries become stricter every day, we find that often crews will come to town with their own gear, but require power.  We have a variety of V-mount or Gold mount batteries in different brands.  All of ours are a minimum of 160 watt hours.  They all offer a Dtap connection for powering accessories.  We also throw a strip of velcro on them for attaching wireless receivers and the like.  Chargers are free with the batteries, and all of ours charge at minimum two batteries simultaneously.