These ones have soft rubber flexible tops to avoid damage and can be seen up to about 70m away.

Small one in photo.
Diameter: 13mm
Length: 122mm
Lithium battery lasts around 15 hours.

Large one in photo.
Diameter: 22mm
Length: 130mm
Lithium battery lasts around 15 hours.

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How about this range that change color from red to green when pulled under the surface of the water. When the light is red it can be seen up to 30m away, and 20m when green.

Lithium battery (BR435) lasts for around 8 hours.
Diameter - from 20mm to 28mm.
Length - from 124mm to 144mm.

Made by National