I couldn't get the Scotty site to load, but it's the
Scotty Powerlock Rod Holder #230. The deck mount I used is the
Scotty Compact Threaded Deck Mount #444. Pics below of the deck mount. It detaches real easy, and does "lock" in place. To insert it into the deck mount you face the far end of the holder towards you, set it into the receptacle, then turn it outboard towards the water. When not in use there's a soft rubber cap that goes over the hole. When you have a rod in the holder you can can turn the end piece on the far end and it rotates around, thereby "locking" the rod into the holder.
Pic from their website:
(as I recall, when mounting the flush-deck mount, you place it so that the word "Scotty" is readable from inside the boat, with the word facing outboard)
Drawing from their website: (you need access to the underside of the deck to install this mount)
Holder removed, cap on deck mount:
Different view:
(That's not a hose in the corner of the deck, that's the cable running to my front tm to the battery)
Still can't get the site to load, but here's a link to a lot of places that carry their stuff. Prices seem to be fairly consistant between the sites:
https://search.live.com/results.aspx?q=Scotty+Rod+Holder&go=&form=QBRE