10Pcs Mini Bubble Spirit Level 10X6mm Circular Bullseye Bubble Levels For Leveling Tripod Telescope 10X6mm, Non-Adhesive - AliExpress
HARFINGTON 5pcs Round Bubble Level 8x5.5mm Mini Circular Bullseye Spirit Levels for Leveling Camera Tripod Telescope Workshop Turntable Pictures Frame, Lime - Amazon.com
Should I trust the bubble level on the mount... - Mounts - Cloudy Nights
What is a spirit leveling? - Quora
DMITER Universal Luminous High Precision Bubble Level with Magnetic Base, 2.36" 60mm ,Thinckness12mm,Accuracy 6'/2,for Telescope, Professional Measuring,Construction (Magnetic) - Amazon.com
Vaonis Bubble Level for Vespera Telescope AC027 - Adorama