Of iron construction.
Similar to the Imperial Gallic J but (1) the corners of the neck guard are more rounded and (2) on the crown above the right eyebrow is fastened a bronze lunar ornament with the horns of the crescent uppermost. On grounds of symmetry (and perhaps a comparison with the Hebron helmet) it might be thought that there should be four of these, one in each quadrant. However, it is now known that this crescent is a patch over a repair (communication from Dr. Klee, Wiesbaden, via Adrian Wink).
It is probable that originally the outer edge of the neck guard was covered by a copper alloy sheet metal channel. A small portion of this survives on the proper right side of the guard. It appears to be held in position by a rivet and piece of sheet brass. There is a similar fitment at the rear centre position of the neck guard.
The neck guard has two embossed ridges while on the occipital region of the helmet bowl there are four such.
The 'eyebrows' are not so well formed as in some examples, having just two embossed ridges. However, inside each ridge pair there is a distinct 'eye', also embosssed. On the centre of the forehead there is another embossed figure, of rhomboid form.
References:
Robinson, H.R. (1975), "The Armour of Imperial Rome", (Arms & Armour Press), p.61.