Northport Back Range Lighthouse
Prince Edward Island Canada
PEI 6-2

(note the stripe. )
This designates a "range" light.
These were in pairs, a front range
and a back range.  The boat captain
would line up the stripes and know
they were in the proper channel

Northport Back Range Lighthouse
Prince Edward Island Canada
PEI 6-3

In the U.S. the Coast Guard
designates them front and rear
range, while in Canada, the rear
is called the back.