Tobruk pits are just one of several varieties of bunkers Germans used during WWII, from Africa to the Atlantic Wall to the Huertgen Forest.  These bunkers varied in size from small machine gun pillboxes to large, multilevel fortifications housing massive artillery pieces and their crews.  There were small portable steel bunkers, as well as bunkers disguised as houses, barns, etc.

Typical Tobruks have an entry chamber leading to the weapons chamber, which has a circular open gun ring in the roof.  From this opening a machine gun could be employed, either on a tripod or mounted in a gun rack that could rotate and elevate to defend against air attacks.  Mortars could also be fired from Tobruks.  And it was common to see turrets from lighter tanks, such as the Pz. II or captured French tanks like the Somua and Hotchkiss, mounted on the casement.  The occupants would typically have the surrounding area sighted and ranged for an efficient and effective defense.

Usually these bunkers were concealed in the ground, with only the gun ring and the door visible.  This made them less visible to the attacker and more protected.

The Tobruk Pit is one of the smaller of several gun emplacements Verlinden Productions offers, and is an early entry in their catalogue.  The VP kit's structure comes in two pieces, a roof and a wall/floor section.  The roof in my kit was more than a 1/4 inch short on one side, and 1/8 inch short on another.  I had to mix up some plaster of Paris to trowel over the gaps.  There is some definition of wood planking used to form the exterior walls, and that is nice.  A round air vent in one wall is not very sharply defined, and would best be covered with a suitably sized part from the railroad section of your local hobby store.  The doorway seems undersized, barely 5 feet tall and very narrow.  There is no door, so you will have to craft one yourself.  Likewise, there is no ring or mount for a gun, so you'll have to scratchbuild one or opt for a tripod-based machine gun.

I added a spare Pz. II C turret I had left over from an Alan/DML kit.  I had to trim the bottom neck of the turret to get it to sit correctly, but it was a simple process and the result is very interesting.

A real life example of the Tobruk can be seen at Bunkers by LC (http://www.geocities.com/Athens/Olympus/6550/).  More information on bunkers can be accessed by doing a search on the World Wide Web.

Aside from the discrepancy in size of the roof piece (VP should check their molds and products more throughly), this is a decent structure and can be placed in many different battle settings.  The two-piece structure and minimal tinkering means it is a good project for youngsters and older newcomers to dioramas.