There are actually 2 different Johnson lifters, the Johnson hylifts are made in the USA, there is another Johnson brand that's imported bodies.... or something like that, but the usa made ones get great reviews. They have a stock style, slow leak and a performance style lifter. I never used any of them, but been looking for a set recently.

One seller I saw is saying something about direct shot performance slow leak, but looks like there are just the regular and slow leak, slow leak being the upgraded style. They are about double the cost.

Edit again, there are the regular, the se or slow bleed and there is also an race version that has variable duration.