Sonnax check balls 10000-12 (.218") are made out of tough, wear-resistant imidized plastic. The Sonnax imidized plastic balls seal better than steel balls because they conform to the separator plate ball seat. Steel check balls are hard and heavy, and wear separator plate ball seats from the repeated high impact of the ball on the seats. Elastomer or rubber check balls seal well. However, the elastomer material wears, reducing the size of the ball. Similar imidized plastic balls have been used on some original equipment late model valve bodies with excellent results. These imidized plastic check balls are not available through the original manufacturer.

• Better check ball seal
• Eliminate separator plate wear from steel balls
• Eliminate elastomer rubber check ball wear