It probably is the only one available. I just got off the phone with the dealer. I asked if they listed a parts manual for a 55 and after a couple minutes he came back and said they didn't list a parts or a service manual for it. He was surprised when I told him they did make a service manual. He said he was gonna call NH and check on the parts manual. When I ordered the 55 I told them I wanted the back up beeper which it plainly states on their website is an option on the 55. The salesman told me I didn't want it but stopped short of refusing to add it to the options list so I dropped it. I have a special purpose for it but I don't want it working all the time so I intend to put a in line toggle switch on it to where I can turn it on and off as I want to. The parts man said they would have to order it and install it after the tractor comes in. The parts man tried to find it after I asked him how much it cost and he couldn't even find it listed for a 55 but it plainly list it as an option on their website. My local dealer doesn't know anything about Boomers because they don't stock or sell them. I am very disappointed in their knowledge of a tractor that they should be selling. They push the Workmaster line and don't care or know anything about Boomers. I think I told you the salesman didn't even know they made a Boomer with a CVT until I told him.