The percussion grenade is made of a elasticized bag of cloth material. It is flexible in the amount and type of munition that could be delivered to a target due to being able to switch up the munition types. For anti-personnel just need to add a little plastic explosive (a quarter to half a stick) along with shrapnel or ball bearings. If anti-armor work is required simply fill the bag with plastic explosive. It offers more flexibility in form then either the Fragmentation Grenades or High-Explosive Grenades but does not perform as effectively as either since it can be considered a 'Jack of all Trades, Master of None.' due to being able to quickly manufacture either with some filler and or shrapnel on the go.
The Percussion Grenade does not work like any other listed type. It instead of being on a time-delayed fuse works on an impact fuse. This means that as soon as the velocity of the grenade drops off, or stops (after being thrown) the internal mechanism used to keep the fuse/percussion unlit trips causing an instantaneous detonation via shockwaves.
A simple process. For either type the fuse must be stuck into the plastic explosive as is normal. Explosive filler is determined by which style the user requires or wants. For anti-personnel half or a quarter of a stick will suffice, the remainder of the 'bag' can be filled with sharp shrapnel bits or ball bearings. For anti-armor someone can simply fill the entire 'bag' with explosive for a larger blast and more damage vs tough armor.