When did BKL start making low & medium mounts?

I have always avoided using them because they were to tall. Thought they just had the one height. Now I was just at their website and see that they have what I always believed to be high mounts. Now they show low mounts as well. So then I checked Pyramid Air and they show Low, medium and high. Can anyone shed some light on this? I want the lowest I can use on my RAW and like the self centering design of the BKL's. Thanks.

Ps. Are there any other options out there for self centering mounts. I have not found any for 11 mm rails. Looking for 30mm.
 
BKL makes the 300 series for 11 mm dovetail mounts. They are good ones. I got them in medium to fit on my MTC Viper Connect (30 mm) and to the bobcat. 

Before using Bkl I was using a cheap set of mounts. Everytime I would shoot beyond my zero distance the POI would shift either to the left or right. The self centering BKL rings fixed the problem for me. They are worth the money. The self centering design is amazing. It clasps your rail from both sides thereby preventing your scope from canting to any side. 

The only other company I know of which makes good mounts is sports match but their mounts are more expensive than BKL. While they don't have the self centering feature they are well made and don't cause POI changes at varying distances.

I've been waiting for BKL to come out with a pair of mounts for picatinny rails since I now use a cricket which doesn't have 11 mm dovetail. Fingers crossed that they make this one quickly. Hope this helps. 
 
Thanks FearnLoading. I know that they are excellent mounts I'm just kind of irked that I didn't know that they made low and medium versions. I have looked several times before and only ever found the high ones. Would have got them a long time ago if I had known. Been using UTG medium's.

On the other hand there's a whole world of firearms picatinny mounts to choose from. Good luck.