The MK.1V general service respirator was introduced in 1926 it was found to have several drawbacks . There were only three sizes, glasses could not be worn underneath and they could not communicate with microphones. The MK.1V Special T Mic was introduced which had four sizes and they could were glasses underneath also it had a moulded area on the left cheek that was designed for a microphone adaptor to connect into.[see pictures].

The Mk IVa Long Hose GSR was developed for use by the Royal Navy, RAF and gunners of the Royal Artillery, whose duties could be hindered by wearing the respirator haversack high on the chest. The longer breather hose allowed the haversack to be worn on the hip.

Light pattern anti-gas respirator and bag introduced in early 1943 originally designed to go with the pattern 1944 webbing it would eventually replace the MK.V general service gas mask. This one is dated 1944. The second light pattern anti-gas respirator shown has a different exhale valve that protrude' s out so a microphone could be attached . This one is dated 1943.Note the cork in the canister on the first mask. This had a tape attached to it and another cork at the other end so both ends of the canister could be blocked when not in use.

Haversack MK.V . Introduced in the early 30s. It has a single flap opening at the top with press stud fastenings at each corner, just below the right hand press stud on the main body sewn into the lining is a length of string or whipcord which goes through the sling and around the chest when worn in the alert position then tied off on the small d-links located half way down the main body of the haversack, on the bottom are three metal drain vents, there are three internal compartments also there is a loop of cloth sown inside the bag on the bottom left for the anti-dimming tube, it has two large metal de-links at the top for the carrying strap to attach to, the strap is threaded through one D-ring then attached to the other one by a flat hook and it also has the small S shaped hook on this de-link to attach to the tab in the middle of the strap when worn in the alert position. I have come across one interesting variation on what must be a very early MK.V bag a metal spring at the bottom of the bag to protect the canister if the bag was dropped,These were removed when the type A canisters were replaced by the type D and E canisters. [see sixth picture].

Haversack MK.V-C and MK.V1. When the anti-gas eye shields and anti-gas ointments were introduced in 1939 more pockets were needed as a interim measure another bag with two pockets was sewn onto the MK.V and it was given a new designation the MK.V-C for converted, around the same time a new mark of bag was introduced the MK.V1 which incorporated the extra two pockets on the back with its own press studs and flap. The next pictures are of the MK.V1. There was also a Haversack MK.Va and MK.V1a which was a modified version of the Mk V and MKV1 Haversack just replacing the whipcord with a waist belt for wearing the haversack on the hip. The belt was made from the same canvas as the haversack and used the same belt buckle as used on the Pattern 1937 webbing belt. The belt clipped on to the brass hoops used originally for the whipcord. The haversack and waist-belt combinations were only used with the Long Hose Mk Va GSR and hence mainly by the Navy and RAF [see the last two pictures of the MK.V1 Haversack].

Haversack MK.V11 was introduced in 1941 in an effort to economize production all the pockets are now internal under one flap with a small sixth pocket being added internally at the top to hold the new pattern of anti-dimming tin with a small length of string attached the lid of the anti-dimming tin and sewn into the lining of the small pocket the small d-links half way down the front the previous marks have gone and replaced by a metal disc on the right hand side, the string sown into the liner on the MK.V11 is now on the bottom left also there is a small outside pocket on the left side for the string, the flat hooks on the strap ends have also gone the strap is now attached directly to the metal loops on the top of the bag and the small S hook and tab in the middle of the strap it attaches to has also gone.

The haversack in use. The haversack may be carried in ether the slung or the alert position . When in the slung position the haversack is on the left side of the body with the sling over the right shoulder. There are two ways to bring the haversack into the alert position. The standard method is as follows " swing haversack to front of body and bring left arm through sling so that haversack hangs straight down from neck. Undo press buttons with sharp pull. Raise haversack on to chest, allowing sling to fall down back. Withdraw whipcord from haversack pass through D-ring on right side of haversack, through the sling behind the back and fasten to D-ring on left side of haversack with a slip knot. Fold haversack flap over between haversack and body." in the alternative alert position to be used quickly in an emergency " the sling is shortened by engaging the tab on the sling with the S hook at the side of the haversack. The haversack then remains on the chest supported from the neck and is secured to the body by means of the whipcord".