The Twin.
Designed to solve several problems related to battery use and weight distribution. It delivers more amperage, hot-swap ability, and more mass below the center of the sled. This allows for a shorter centerpost and / or higher gimbal depending upon the operator's setup and choices.
The Twin provides the following advantages:
º Hot-Swap of battery while in use.
º Rigid design that is no wider than the battery.
º Functions in Steadicam, hand-held or lighting mode.
º Resettable circuit breaker.
º No voltage back-charging.
It is best mounted directly below the centerpost. This greatly reduces any chance of vibration and allows the added mass of 2 batteries at the bottom without altering the fundamental front-to-back weight distribution. Jerry Holway's V-Lock Bumper is a popular addition here. It prevents inadvertent depression of the release button that's a common issue with V-Mount battery users. Reference link at the top of this site for details.
Mounted on Kat Kallergis' Tiffen Steadicam M-2
Twin in Hand-Held Mode
This build by Tom Wills, S.O.C. allowed him to move more mass behind his shoulder, affording a bit more counter-balance to the rest of the camera build resting in his hands.
David Svenson's M-2 with The Twin in low-mode
Twin in use during New Year's Eve in Times Square, NYC.
Here's the Twin in Lighting Mode. The electrician holding the LED panel typically is trying to manage a unit that's completely top-heavy and quite uncomfortable to hold hour after hour. By using the Lighting accessory kit, the Twin can be attached to a grip arm knuckle. The light panel rests into the other end of the arm. This makes for a nicely balanced rig. The weight of the light at the top ( with no battery ) is balanced with the weight of the Twin and 2 batteries at the bottom. Use of a P-Tap cord delivers the power from the Twin up to the panel back. The electrician shown below found the build to be much more manageable than in previous years for the 3 + hour show.
Frequently the temperatures are below zero for the annual New Year's Eve broadcast. Previous years' shows had issues with batteries failing while on-air and in mid-shot. The solution was an insulated housing for the Twin. Hand-warmers were placed into the housing to keep the air warmer near the batteries. It rained that year and so the soft padded housing was wrapped in sheeting to keep it dry.