head height in the box

[PAblue87]

I have ben working in the Box position and I am confident that I call a good game. It seems to me that my head height was always consistent, however my evaluator told me I have a tendency to dip to far. I have heard a lot of a lock in mechanism and was wondering if anyone could give some insight on what a good one would be. I am looking for a way to assure I am always in the same place. Thank You in advance for your input.