Please note: This text was taken directly from the manufacturer.
This clever adapter precisely centers any 1.25" accessory in a 2" focuser. Whereas standard 1.25" adapters use a thumbscrew, which pushes an inserted barrel laterally, i.e., off center, the Centering Adapter employs a helical compression mechanism that precisely centers the accessory as it is tightened in place. This adapter is especially useful with reflector telescopes for critical centering of a collimating device. It's also ideal for centering eyepieces and imaging cameras on the center axis of a telescope's light path. Made of machined, anodized aluminum, with a knurled twist-lock ring. Barrel is threaded for 2" filters.
