Pick your shape:  Pyramids/Tetrahedrons, Angle Cut Cylinders, Triangles, Cones etc. (see shapes below)   
Pick your size:  each shape has an A, B and possibly a C measurement.  Pick the one that fits your application.
Pick your composition: 
HD:  HD is a very hard composition with excellent fracture resistance.  Well suited for polishing parts.  Developed for use in high energy machines.  Excellent results when used with accelerated chemicals in vibratory applications.  110 pounds per cubic foot. 
LL:  This versatile bond has light cutting ability and long wear life while producing excellent surface finishes when combined with proper compound. 90 pounds per cubic foot. 
MC:  A popular bond with excellent cutting ability yet a wear rate only slightly higher than our LL bond.  Imparts a light matte finish to all metals. 
90 pounds per cubic foot.

Recommendation:
For General Cleaning and the best overall results with the least amount of lodging and the longest life try
U056-PT114MC.
 For General Cleaning and good results with some lodging try U056-ACTS118-LL or U056-45ACC58-LL.  For Polishing and
Brightening try U056-45ACC12-HD or U056-22ACTS118-HD along with U056-0024-Q5 Water Based Cleaning Compound.

U056-22ACT2-LL.....22 Angle Cut Triangle A=2, B=5/8
U056-22ACT2-MC.....22 Angle Cut Triangle A=2, B=5/8

U056-22ACT112-LL.....22 Angle Cut Triangle A=1 1/2, B=1/2
U056-22ACT112-MC.....22 Angle Cut Triangle A=1 1/2, B=1/2

U056-22ACT78-LL.....22 Angle Cut Triangle A=7/8, B=5/16
U056-22ACT78-MC.....22 Angle Cut Triangle A=7/8, B=5/16

U056-22ACT14-LL.....22 Angle Cut Triangle A=1/4, B=1/4
U056-22ACT14-MC.....22 Angle Cut Triangle A=1/4, B=1/4

U056-22ACC78-LL.....22 Angle Cut Cylinder A=7/8, B=1 5/8
U056-22ACC78-MC.....22 Angle Cut Cylinder A=7/8, B=1 5/8

U056-22ACC516-HD.....22 Angle Cut Cylinder A=5/16, B=3/4
U056-22ACC516-LL.....22 Angle Cut Cylinder A=5/16, B=3/4
U056-22ACC516-MC.....22 Angle Cut Cylinder A=5/16, B=3/4

U056-CONE34-LL.....Cone A=3/4, B=7/8
U056-CONE34-MC.....Cone A=3/4, B=7/8

U056-CONE114-LL.....Cone A=1 1/4, B=1 1/4
U056-CONE114-MC.....Cone A=1 1/4, B=1 1/4

U056-VCC2-HD.....V-Cut Cylinder A=2, B=2
U056-VCC2-LL.....V-Cut Cylinder A=2, B=2
U056-VCC2-MC.....V-Cut Cylinder  A=2, B=2

U056-VCC1-LL.....V-Cut Cylinder A=1, B=1
U056-VCC1-MC.....V-Cut Cylinder A=1, B=1

U056-VCC58-LL.....V-Cut Cylinder A=5/8, B=5/8
U056-VCC58-MC.....V-Cut Cylinder A=5/8, B=5/8

U056-VCC38-LL.....V-Cut Cylinder A=3/8, B=3/8
U056-VCC38-MC.....V-Cut Cylinder A=3/8, B=3/8

U056-ACTS118-LL.....22 Angle Cut Tri-Stars A=1 1/8, B=5/16
U056-ACTS118-MC.....22 Angle Cut Tri-Stars A=1 1/8, B=5/16