The grenade is of the percussion type with an "Always" action. The cylindrical body with a screwthread around the centre is painted red and is fitted with an unpainted safety cover of aluminium which fits over one end and extends over a portion of the side. The head of the safety cover is embossed "SOCIETA ROMANA". The grenade is approximately 3.2 inches long, 2 inches in diameter and weighs 6 oz. 10 dr. A paper wrapper, in which the grenade is packed, bears the printing "SOCIETA ROMANA CONSTRUZIONI MECCANI-CHE".

The body of the grenade is of tinned plate and consists of two cup-shaped portions with a pressed screwthread at the mouth for assembly and a recess at the closed end, which forms part of the arrangement to obtain "Always" action. When screwed together the cups secured by a locking wire which is located on the inside of the pressed threads in the base cup and is bent to form a projection which passes through coinciding holes in both cups and protrudes slightly from the exterior of the assembled body. The upper cup carries a stud near the periphery of the head and has slots in the wall for the insertion of the safety strip and safety bar. The stud is used as a means of coiling a length of light chain which connects the safety cup to the safety bar.

A steel collar is located in the recess inside the head and base of the body. The collars are seated in similar recesses in the charge container and cuter container, for which they from the end supports.

The outer container is of tinned plate and is in the form of an inverted cup which carries a needle inside at the closed end and fits over the charge container. A spiral spring is held between the upper end of the outer container and a bearing plate. The bearing plate has a central hole for the needle and is supported by a shutter device when the grenade is armed. The shutter device consists of a tinned plate arm pivoted at one end on a pin which is fixed in an aperture in the wall of the outer container, whilst the other end protrudes through another aperture on the opposite side of the container. The pro-truding end is held in engagement with an inclined undercut on a projection formed in the aperture by a spiral spring. The spring extends around the outside of the container, bet-ween the two apertures, and is tensioned between the protruding end of the shutter and the pivot pin. The aperture in which the undercut projection is formed also has a slot through which the protruding end of the shutter is moved, by the spring, when feed from the undercut. The shutter is a thin, flat plate tapering from the centre towards the ends. A hole, eccentrically placed at its widest part, is not coincident with the needle hole in the bearing plate when the shutter is held by the undercut projection. Two additional apertures are formed diametrically opposite in the wall of the outer container, at right angles to those for the shutter, to receive the safety bar and the safety strip. The bar extends diametrically through the outer container between the bearing plate and the shutter and is bent at the outer end to fit over the ring of the safety cover. The bar is attached to the ring by a 2.5-inch length of light chain. The safety strip is of thin brass and extends diametrically through outer container and the body of the grenade between the shutter and the head of the charge container. A vulcanized gripping tab is attached to one end of the strip which passes over the cover ring. The other end of the strip emerges below the ring and is bent upwards over the ring and the safety bar. A steel sleeve, wound with wire, is fitted externally to the outer container to provide fragments for destructive effect and the weight necessary for "Always" action.

The cylindrical charge container is of tinned plate and has a 1.5 oz. filling of T.N.T. with a central detonator. The percussion cap at the head of the detonator protrudes through a central hole in the closing cap of the container.

The safety cover is shaped to fit over the head and down one side of the grenade. The cover carries an encircling ring secured in an inclined position by bent tongues formed in the cover. The cover is retained on the grenade by the safety strip and bar engaging the ring to which the chain of the safety bar is also attached.

Before throwing the grenade the safety strip is removed by pulling the vulcanized tab. The withdrawal of the strip releases the ring of the safety cover. During flight the cover leaves the grenade and, functioning as a drouge, extends the chain and withdrawas the safety bar. The charge container with its detonator is then held off the needle in the head of the outer container only by the intervening spiral spring and the shutter. On im-pact the charge container is forced further into the outer container. The manner in which this movement is brought about depends upon the position of the grenade on im-pact. With a head-on strike the charge container is carried into the outer container by momentum. With a base strike the couter container, weighted with its steel sleeve and wire winding, is carried down over the charge container by momentum. With side impact the collars engaging in the recess at the head and the base of the containers are tilted by the side thrust and thus cause a telescopic movement of the container. The entry of the charge container forces the shutter clear of the undercut projection, and as it is tur-ned on its pivot by the tension spring, the hole in the shutter coin-cides with the hole in the bearing plate. Whilst in this position the spiral spring is further compressed and the needle pierces the detonator. Unless the grenade is thrown with considerable force the shutter will not be released on impact and the grenade will fail to function.