Leica GDF321 Pro Tribrach w/o Optical Plummet

The GDF321 (and the GDF322) Professional 5000 series tribrachs are the highest grade professional tribrachs from Leica. Individually tested. Suitable for all high-angular accuracy requirements. The torsional rigidity (or hysteresis) of the Professional 5000 Series tribrachs amounts to a maximum of 1″ (0.3mgon). All Leica original tribrachs comply with the strict specifications and quality standards of Leica Geosystems. Your choice should ideally be made according to your individual accuracy requirements. The tribrachs in the 5000 series are recommended for all tasks that require angle measurements of 3″ or better. Due to the minimal torsional rigidity (or hysteresis), we recommend use of the Professional 5000 Series for all motorized instruments. The accuracy with which a tribrach returns to its starting position once the instrument has stopped, is called torsional rigidity or hysteresis. This hysteresis is the relative movement between the top plate and the base plate of a tribrach that occurs through the rotation of a TPS instrument. The hysteresis has direct influence on the angular accuracy of the instrument – and that speaks for the original. To optimize the hysteresis as Leica Geosystems has done is complex and calls for the highest precision: a movement of the top plate to the base plate of 0.3µm corresponds to an angle error of 1″. Especially motorized instruments with their high acceleration and brake power require tribrachs with very high torsional rigidity. The foot screws are maintenance free and have a larger diameter. This allows for fine adjustments, even when wearing work gloves under difficult environmental conditions. 777508