Updated Post- My thanks to Ernst-Udo Peters for some more information on this pack that has allowed an update.
The Canadian Army 82 Pattern webbing set was issued with a small haversack, mounted on the rear of the belt that was officially known as a ‘Small Field Pack’ but colloquially got referred to as a ‘butt pack’ due to its position over the wearer’s posterior:This pack was designed to carry a soldiers essential kit to sustain him in the field for small periods of time. It is made of green nylon and is a small squarish shape:Two distinct variants exist, an early example with friction buckles to secure the top flap, and this later example that came into use in around 1986. It has a top flap that is secured on the front by a pair of dark green ‘Fastex’ buckles and adjustable nylon straps:Under this a draw string is fitted to help keep the contents weather tight:With a plastic friction fastener to secure the draw string tight:Again the earlier variant of the pack has a slightly different cord lock, being made entirely of green plastic up until 1986. The manual provides a nice line drawing of the pack:The pack is typically worn on the back of the belt:To attach it the standard 82 pattern plastic post fasteners are fitted to the rear of the pack:These have the same velcroed tabs as the rest of the 82 pattern items, once the plastic posts have been inserted into the eyelets the two tabs are folded over and secured around the belt for added security:Above these are two further tabs that attach to the Yoke we looked at here:The 82 pattern manual offered two alternative ways of wearing the pack, with the option of attaching a strap into two friction buckles:And wearing it over the shoulder:This pack was never big enough, and troops often supplemented it with other larger packs in the field.