The Pro-Ject Signature Counterweight Insert is a genuine spare part designed for use with the Pro-Ject Signature series tonearms, specifically the Signature 10 and Signature 12 models. These tonearms sit at the apex of Pro-Ject's tonearm range, featuring an oil-damped uni-pivot bearing and an S-shaped aluminium tube machined on high-precision CNC equipment. The counterweight assembly on these tonearms accommodates cartridges from 5 to 25 grams (up to 37 grams including the supplied aluminium headshell).
The 30mm diameter insert is the smaller of the two insert sizes available, suited to balancing cartridges at the lighter end of the compatible range. Having a selection of inserts gives users additional flexibility when changing between cartridges of different weights, allowing for precise tracking force adjustment without compromising the tonearm's performance. The 45mm version is also available separately for use with heavier cartridges.