How much to charge for underwater photo gear to rent

Just wondering what a good rate would be to rent out my underwater camera gear, which consists of Ikelite housing for D80, D80, 10mm Dome port, 12-24 port and 2 DS-125 Strobes. This is a favour to a guy for one shoot, who is a commercial diver and aprox 2 days uw use. Not good practice I know, but trust him to make good on any damage and or replacement. Any suggestions?

I beleave the going rate is about 3% of the total value of the kit per day.

Phil Rudin