Check the listing for details. BowJax Ultra BowJax II String Silencer, 4 Pack. Black. Color: Black, Condition: New with tags. Listed at 10.75 USD. BowJax Ultra BowJax II String Silencer, 4 Pack. BlackStronger, longer lasting. Due to popular demand, we have Ultra BowJax II available. They are made to slip over the string and held on by friction instead of cable ties. These are high performance string silencers, reducing string noise by up to 90%. They are known to increase velocity 1-3 fps. Wt. 26 grains. Mfg Number: 1036 WARNING: This product may contain chemicals known to the State of California to cause cancer and birth defects or other reproductive harm. For more information, go to www.P65Warnings.ca.gov.WARNING: This product may contain chemicals known to the State of California to cause cancer and birth defects or other reproductive harm. For more information, go to www.P65Warnings.ca.gov.WARNING: This product may contain chemicals known to the State of California to cause cancer and birth defects or other reproductive harm. For more information, go to www.P65Warnings.ca.gov.