An embarrassingly noob question for someone who's been doing this for almost a year: Well, are they?
Blaro
All penstyle and fit the 801 style PV's. There is also the BE112 - and a few other that are not very popular these days - a KR108 model and SE101 model.
BE112 and DSE801 have 4 air holes.
Joye302 and RN4072 have 2 holes.
And then there's the 'high' and 'low' bridge. And that can vary.
RN4072 is usually low bridge (better for cartridges in that it allows maximum room for the 801 style cartridge).
BE112's and Joye302's I have are also low.
Drippers sometimes prefer the 'high bridge'.
I've seen 801's that are high and low.
The ohm ratings run from about 3.4-3.8 and now there are LR 801's and also cartomizers in that style.