volodar, the sliding weight was hollow except for a small amount of lead that was already in it. I took the weight into my local grain company and ask why their would be lead in there and for what purpose. Gary is one of the managers and he told me it was probably to balance the beam. One of the holes in the bottom of the weight was bored clear through into the middle of the weight and that is where I poured the lead into. I wished I had weighed the thing before and after I filled it. I will weigh it and post the results soon. Yes it was hollow. Thanks for the question.