2008 F-350 blown stop/turn trailer fuse

I think I blew the stop/ turn trailer fuses on my 2008 F-350. I located the fuse box under the hood and the manual said that fuse #21 and #22 are for the right and left trailer stop/turn lights. From what I can tell from the diagram the fuse appears to look like a little black box instead of the thin clear ones I am used to seeing in a vehicle.

Am I reading the diagram correctly? If I am will Napa or Pep Boys carry that style of fuse? Do I have to replace with that style?

Thanks
Matt