Free to use; extras unlock with a one-time purchase. On a trip three things run out: your watch's battery, the daylight and your own energy. Cairn shows the three side by side, counts the days of your trip, and tells you whether the battery lasts to the last day. Everything comes from the watch itself; no phone connection or weather download is needed. Made for the Instinct 2, 2S, 2X, 3 Solar and E (40/45 mm) and the Descent G1, where the trip day sits in the round window, and also on round fenix, Enduro, tactix, quatix, Forerunner, MARQ, Descent Mk2 and vivoactive watches with a memory-in-pixel screen. - Battery: the charge as a bar and the days the watch estimates it has left. - Daylight: the share of today's daylight still ahead, the time to sunset and the sunset's clock time; after dark, the time to sunrise and its clock time. - Body: Body Battery. - The trip: set Trip start and Trip end in the settings, and the window shows the day of the trip (day 3 of 5). - Today's climb, descent and distance under the three rows. Customize it in the Connect IQ app. The trip dates and the colours (black on white, or white on black) are free. These are marked with a star in the settings and can be used during a 7-day trial, then stay unlocked for good with a one-time purchase ($3.99) at murmurgram.gumroad.com/l/cairn: enter the 12-character Watch face ID from the settings at checkout, and type the key you receive by email into Unlock key. - Time font: five more styles for the time besides the dot matrix: condensed, segment, stencil, outline and geometric. - Battery against the trip: OK, or SHORT, after the battery's days, counted against the days left to the end of your trip's last day. - The trip's climb, descent and distance, with a bar for each day's climb. - The highlight: the trip day, the battery against the trip (spare or missing days), altitude, solar intensity, or the pressure trend over three hours. The face keeps each day's climb and distance while it is on the watch (for up to 30 days), so wear it from the first day of the trip. The daylight uses the watch's last GPS position (any activity with GPS records one). Watches that do not estimate battery days show the charge in percent and no battery check. Privacy: everything is computed and kept on the watch. Nothing is sent anywhere. If you buy the unlock, Gumroad handles the payment and your email address is used only to send your key and for support. Permissions are used for the position (sun times), sensor history (Body Battery, pressure) and the user profile.

A starred Time font setting gives a choice of six time fonts (the dot matrix stays free).