Sap

Saps, also known as a slappers, slap jacks, or beavertail saps, were a type of light, non-lethal martial melee weapon.

Description
Saps were a lead rod or disk hammered somewhat flat and wrapped in leather, then fitted to a spring handle. The handle could either be an actual spring or a flexible strip of steel. Lead shot (small pellets) was ocassionally used in place of a solid piece of lead.

Weaponology
Saps were designed to deliver non-killing blows, dealing out non-lethal damage for roughing someone up or knocking them unconscious. Knowing where to strike and getting in close enough to use a sap required some skill and thus they were considered a martial weapon. It was very difficult, but not impossible, to kill someone using a sap by striking them in their most vulnerable areas.