What it is
The Aer Day Sling 4 is Aer’s everyday sling. The official page calls it “the everyday sling made for travel”: a wide-open main compartment, a quick-access front pocket, and a hidden back pocket for a passport or cards.
Aer sells two sizes on the standard ballistic-nylon sling. Day Sling 4 is 2.5L at $79 with a padded pocket for tablets up to 8.3”. Day Sling 4 Max is 6L at $95 with a padded pocket for tablets up to 11” (official Max page reviewed the same day). Both list YKK zippers, Duraflex hardware, a hidden smart tracker pocket, and a removable, repositionable keychain.
This listing is the slings lane on Unseen Carry. Backpacks and briefs are separate pages.
Who it’s for
Use it if you want one shoulder for a tablet and the day’s admin: front pocket for grab items, secure back pocket, tracker pocket, keychain. Official copy is daily carry and travel, not a camera bag.
Skip it if you need a 13-inch laptop in the sling. That is a brief or a pack. Aer’s own City Pack Pro 2 is the backpack on this site. Do not pay X-Pac or Ultra money unless you want that fabric.
Standout details
- Official 2.5L: 9.5” L x 6” H x 3” D, 2.5L, 0.74 lbs. Official Max: 12” L x 8.5” H x 4” D, 6L, 1.11 lb.
- Exterior: 1680D CORDURA ballistic nylon (bluesign approved). Interior: lightweight ripstop nylon (bluesign approved). YKK zippers. Duraflex hardware.
- Padded tablet pocket: 8.3” on the 2.5L, 11” on the Max.
- Quick-access front pocket with drop-in organizers. Secure back pocket for passport or wallet. Hidden smart tracker pocket. Removable, repositionable keychain. Hanging loop.
- Standard colors listed on both size pages: Black, Navy, Olive.
- On 2026-08-27 both official size pages showed Sold Out with an email-when-in-stock form. Price and specs are from those pages. Stock moves. Check Aer before you buy.
- Fabric upgrades on Aer’s site the same day: X-Pac and Ultra. Those are material and price changes, not a different bag job.
Honest verdict
Use it. For a work day that does not need a backpack, this is the current Aer sling: tablet pocket, real admin pockets, the same ballistic nylon as the City Pack Pro 2. Start at the $79 2.5L unless you know you need the 11-inch tablet and 6L Max.
Do not buy this if you actually need a laptop in the bag. Re-review if Aer changes the tablet spec or the $79 / $95 prices.