.177 Bolt probe O ring pack of 5 to fit our modified bolt probe. For the .177 SMK QB/XS/TH 78/79 models that have our tuning kit fitted, as the standard seal is different.

You can watch the video for free on this site under SMK Stripdown Video on the left side panel store links, at the moment it is the fourth one down. This video is on the XS78 but the XS 79 with the large 88 gram bottle has similar parts inside.

Always check the power to make sure the gun does not exceed your limit, after changing any parts.