The water in my kitchen sink goes out very slow and after I used this product (with maximum length of the wire available) the sink was completely blocked and the water in the sink stayed there. I assumed all the dirt being pushed down along the pipe blocking completely the water. So I bought an electric one with longer available length and so it went deeper and the water started to flow again.

In fact, it has nothing to do with a pencil case. This device is used when a pipe is blocked.