Related Clues:

• It helps helmsman manage after risks leaving loch
• Sub feature
• Sub need
• Aid which helps you see pier and copse if blurred
• What may help little person to see fairy's garment
• One sees what's up, in the main
• Optical instrument that provides a view of an otherwise obstructed field
• Overseeing helper?
• What improves vision, in the main?
• Submarine viewing device
• Almost choke policeman with electronic spying device
• Pose price mistakenly for part of a submarine