That the M981 is based on the M113A2 APC is immediately apparent. The external fuel tanks are mounted on the vehicle's rear, and the smoke grenade launchers are present on the front hull. The multitude of antennas attest to the amount of radio equipment necessary in the vehicle. The turret head is in the stowed position on this vehicle, pointed down and to the rear. The commander's periscope is visible just behind the forward antenna guard.
More details of the smoke grenade launchers and the T130E1 track are visible in this front view. The trim vane on this vehicle is the high-displacement type also found on the M163 VADS.
The height that the targeting head added to the hull is illustrated here with the M981 parked next to an armored command post carrier M577A2 with its raised passenger compartment.
The underside of the partially-open driver's hatch is visible in this image. The round periscope mount can be seen to the front, and the internal locking mechanism is on the inboard side. The commander's machine gun mount is visible on his cupola, and the trim vane control handle is on the front slope in front of the driver's position.
When stowed, the cheeks of the hammerhead rest on supports. The openings for the targeting and ranging devices are apparent in the front plate of the turret, and more antennas are visible on the other side of the vehicle. The entry door in the rear ramp is visible, as is the vision block in this door. Brackets for mounting telephone cable reels are visible below the taillights.
Further details are provided here of the antenna mounts, cable reel brackets, and (oversprayed) taillights.
Stowage brackets were provided on the rear fuel tanks for liquid cans or the M13 portable decontaminating apparatus.
The targeting head was placed at the end of a pair of erector arms that were connected to the commander's cupola. The cupola mount for the M60 machine gun can be seen just behind the commander's periscope. The red handle is for external activiation of the vehicle's fire extinguishers.
The roof of the vehicle was a non-slip surface. Details of the hammerhead's supports and its connection to the commander's cupola can be seen here.
The underside of the hammerhead turret is shown in this picture.
This image is peering through the open ramp door. The driver's position can be seen to the front left; a folding bench on the left and a single folding chair on the right provide seating for the rest of the crew. Note the camouflage finish on the inside of the roof hatch so that it does not contrast with the rest of the vehicle when open.
The right-side wall of the passenger compartment was home to racks for the various radios installed, which might include an AN/VRC-46, three AN/GRC-160 tactical radio sets, a digital message device, and the vehicle's four-channel intercom. The hoses to the front right were part of the NBC filtration system.
The left wall featured ledges and footman loops to secure stowed equipment, which included an AN/TAS-4 thermal sight, two boresight collimators, a laser designator/rangefinder backpack, and an AN/GVS-5 laser rangefinder. The large hose from the fuel filler on the roof is obvious at the left rear of the vehicle.
The inside of the Emerson hammerhead turret is shown here, with the turret facing the rear of the vehicle. The commander's periscope can be seen on the left of the image.
This lower view between the bench and folding seat reveals the padding around the turret ring of of the hammerhead turret. A dome light is on the ceiling between the roof hatch and the NBC system on the right, and the driver's open hatch and periscopes can be seen to the front.