Apparently all are not created equal. Mine has two set screw style screws that are adjustable for 510 contact top and bottom. You might want to buy from a vendor who shows both ends in the picture.
I was looking at them on FT a year or so ago when I was having problems with a loose 510 on an old mod. I found it quite hard to figure out which of the multitude of offerings was adjustable on both ends. The descriptions weren't very clear.
On some of them it looked like one end was connected to an outer barrel and you had to adjust it by moving the barrel against friction with a rubber insulator. The other end was adjusted by a screw that went into that outer barrel. But the descriptions were so inscrutable that I gave up.