I have an HHA OL-5510 for sale or trade. It has the smaller scope with armor pin. I have also added the 2nd and 3rd axis extension adjustment and I have all but one sight tape that will come with it. I am pretty sure it's the 55 series, but it may be the 50 series. Anyhow, it's the one with the rheostat to control the amount of light to the fiber in the pin. The ONLY reason I am getting rid of this sight is because I switched to a Limb Driver Pro-V on my new rig and the slider bar gets in the way of the cord on the rest. The sight is in excellent condition, and has zero rust and only a couple of minor blemishes that are purely cosmetic. I will list the sight for $130, but I would prefer to trade for another sight. I am looking for another single or possibly a multi-pin adjustable sight, such as the Black Gold Ascent, CBE Tech Hunter or another similar to these. I would also consider sights with a dovetail bar like a Spott Hogg Hogg-it. If I need to add some cash to make the difference on the trade that's no problem. Please PM me with any offers. If I end up selling, I prefer Paypal for payment. Thanks for looking and I will post some picks when I get back to the house. Thanks all!!!