Mystara and the Path to Immortality
Here are several types of shields, of varying sizes, weights, costs and associated rules.
Small Shield, SIZE=S, AC-1, COST=5gp, 50enc
Medium Shield, SIZE=M, AC-2, COST=10gp, 100enc
Large Shield, SIZE=L, AC-3, COST=15gp, 200enc
Tower Shield, SIZE=L, AC-4, COST=25gp, 300enc
Small Shields are equivalent of bucklers and can be used by any race (small creatures count this as a Medium Shield).
Medium Shields are equivalent of viking round shields or medieval foot shield, and can only be used by medium sized creatures.
Large Shields are kite shields and can only be used by when mounted.
Tower Shields are huge covering from head to foot, can only be used by medium creatures with strength 16 or greater.