I see two 'tunnels' when using my binoculars, is this normal?
No. The distance between the eyes, called 'interpupillary distance', varies from person to person and your binocular must be adjusted accordingly.
1. Hold your binoculars in the normal viewing position.
2. Grasp each barrel firmly. Move the barrels closer together of further apart until you see a single circular field. Always re-set your binoculars to this position before using.