1 Converted from megapascals (MPa)

Inch has one strength level, alloy steel.

Metric has two, property classes 12.9 and 8.8.

• 8.8 is about 30% weaker.
• 8.8 is also 20 - 50% less expensive.

Caution: Don't substitute 8.8 for 12.9. For metric M5 and larger, the property class and manufacturer's I.D. is marked on the head.