The original ones my dad and a few of his friends made 30 years ago had the spool out of the box on top. This would ice up. Not an issue with it inside although I still use the others also. DT
Here is a pic of the Bite Me Box Tipups. I like the fact that the flag does not have the spring tension that adds resistance to the bite. Sensitivity is a big deal for walleye and panfish.
I use the Bite Me Box Tip Up and love it. I use to use the underwater tip ups and got sick of tangled lines, wind trips, and frozen holes. I dont have those problems now and wind up at the end of the day is a breeze! I bought mine online. The cool part was it came completly assembled and ready to fish. Now when we get a bite we yell BITE ME! It sounds better than flag. Try them.