Found these online looking around. I did some research and though not officially listed (ES lists a 5mm eye relief but this is assumed to be a misprint) and the eye relief is around 12mm to 15mm. I'd go with the 12mm. They have a 35mm, 30mm ($49.95 each) 15mm and a 10mm available for $29.95 each. http://www.optcorp.com/ProductList.aspx?uid=30-718-1511-1786 I don't own any of these though for $30.00 I may try the 15mm and use it as an outreach eyepiece. The 30mm and 35mm look similar to the Orion Q70 line and the ones similar to them. -- Jay Eads