APM Telescopes offers a whole series of Ultra Flat eyepieces. The focal lengths are staggered from 10mm, 15mm, 18mm, 24mm and 30mm. The FOV is 65° - the 30mm eyepiece has a FOV of 70° and a 2" connection. The FOV are clearly visible. The eyepiece series up to 24mm is ideal for large APM binoculars.