Hook used for measuring ice thickness also through small holes made by ice poles. Lines at 2-8 cm's. Total length 12 cm. Manufactured in Finland.
Usage:
Hit a hole in the ice with an ice pole (poles are able to penetrate about 7 cm of ice in one blow)
The hook is poked into the hole
The end of the hook will turn up against the underside of the ice
The upper ice surface level matching the line on the stick is the thickness
Number five is above the line for 5 cm (2inch)
Remember that some ice may have cracked away from underneath. Look for the deepest position.
Ice strength is measured in several ways. Thickness is only one of those variables.