Bottle neck jack

I read a couple of weeks ago that you need a bottle neck jack for changing a tire. OK, being a female and not very automotive savy, I figured, OK, I'll just go on Amazon and type in bottle neck (or bottleneck) jack, and there and behold I would see what the heck it is and what it looks like.. Well no such luck. I even googled it and still nothing.

Could a slightly more mechanically minded person, please give me a link to what one looks like, and also the recommended weight it needs to be. I have a 2007 TM 2619.

One other question: Water pressure gauge. There seems to be a wide range of costs on these. I am getting tapped out with all my new purchases to be travel ready, so I don't want to spend more than I need to, but on the other hand I don't want to get something that will not be sufficient. Are the metered ones really necessary? Any recommendations on one of these?