For the Palladium RPG, the S.D.C. of shields are as follows:

Small Large
Wood 13 25
Leather 9 20
Wood & Leather 21 35
Iron 30 55

Characters with W.P. Shield get +1 to parry at levels 1,3,6,9,12, and 15. A shield can be used in one hand and a weapon in the other. +1 to strike with shield (1D4 damage) at levels 4,8, and 12. There are no bonuses to strike when thrown.