Features :

* including Lanyard & skylon case calibrated for an accuracy
* framework is of corrosive resistant light-weight aluminium
* scale card is supported by a jewel bearing assembly
* all moving parts are immersed in a damping liquid inside a high strength hermetically sealed plastic container
* weight: 4.2 oz
* size: 2.75" x 2" x 0.625"
* optical scale graduated in degrees from 0� to +/-90� and from 0% to +/-150%
* table of cosines imprinted on back of instrument
* can be read directly to one degree or one percent
* can be estimate to 10 minutes or 1/5 of 1 per cent (applying to readings around the zero level)