Orion 5528 T-Thread Spacer Ring Kit Use the Orion T-Thread Spacer Ring Kit to achieve proper spacing with astrophotography equipment and avoid fuzzy, out of focus images Includes 5mm, 10mm, and 25mm T-threaded spacer rings - mix and match depending on your needs Each ring features an easy-grip knurled exterior for convenient use Glare-reducing threaded interior maximizes contrast