Spread horseradish on 1 side of each ham strip.
Place 1 oyster on each ham strip; roll up and secure with wooden pick.
Arrange on broiler pan.
Combine butter, lemon juice and garlic powder in small cup.
Brush each ham roll with some of the lemon-butter.
Broil, 5 inches from heat, 10 to 15 minutes or until edges of oysters curl, brushing occasionally with the remaining lemon-butter.