1) Product: Red fluted multi-purpose drill bits 
Cobalt and tungsten carbide tip,Chrome vanadium steel shank
118 degrees of carbide angle,professional quality
Metric size: 3/32"-1"  Inch size: 3-25mm;special length are available upon your request

2)Picture of Multi-Purpose Drill Bits

3/16" 3-1/2" Straight

7/32" 3-3/4" Straight

1/4" 4-1/4" Straight

9/32" 4-3/8" Straight

5/16" 4-1/2" Straight

11/32" 5" Straight

3/8" 5-15/16" Straight

13/32" 6-1/4" Straight

7/16" 6-1/4" Straight

15/32" 6-1/4" 3/8"

1/2" 6-1/4" 3/8"

9/16" 6-1/4" 3/8"

5/8" 6-1/4" 3/8"

3/4" 6-1/4" 3/8"

7/8" 6-1/4" 1/2"

5) Drilling Instruction

Please follow the speed and technique instructions below

Hardened Steel and Iron            2000—4000 RPM (Lubricant)

Masonry/Concrete                 2000—4000 RPM (Percussion)

Stainless Steel                    1500—2500 RPM (Coolant)

Glass/Tile/Granite                  300—600 RPM

Plastic and Laminates               300—600 RPM

Solid Surface Materials              300—600 RPM

Wood and Composite                500—1000 RPM