Every Yupik hunter carried a harpoon and almost every harpoon had a durable "ice tester" at its base.  These allowed the hunter to test the stability and strength of the ice pack as he hunted his way across it.  This basic bulletproof design is thousands of years old and this particular specimen is easily 500+ years given its patina.  Ice testers came in many sizes and designs, the more intricate ones could be interlocked so that two hunters in separate umiaks could give each other extra stability while traveling side by side.  This specimen has tested its last ice flow but the material and the lines can beg for it to be repurposed.   Please look at my other Alaskan Artifacts.