CarbaCap

Q: Is there a missing O-ring inside just pass the threaded area of the CarbaCap?
A: The CarbaCap has only two O-ring's. The first O-ring is on the metal pin inside the cap. This O-ring is compressed against the inside of the cap by a spring. This remains closed until pushed inward by the injector. The second O-ring is on the outside of the cap and maintains a tight seal between the injector and the cap. Many CarbaCap users think there should be an additional O-ring where the PET bottle threads onto the cap. There is a special ridge inside the cap called the Gas Retaining Wall (GRW). This part of the cap extends directly inside the PET bottle sealing it with a cap without the need for an O-ring. It is not recommended to add an additional O-ring in this area. If an off market O-ring is placed in this area there are two major factors to consider. (1) Most O-ring need a space to expand when compressed. This would crack or damage the Gas Retaining Wall inside the CarbaCap. (2) The additional O-ring would prevent the cap from safely off venting pressure when uncapping. This could cause the CarbaCap to become an unsafe projectile. As the CarbaCap is not designed to accommodate an O-ring in this area it would be detrimental and counterproductive. The Gas Retaining Wall on the CarbaCap should be sufficient for standard use.