Came across it while looking for laptop sleeve to fit 15.6" laptop and it seems to have good reviews.
Dell Essential Sleeve 15 (ES1520V)
Product Type: Notebook sleeve
Colour: Black with silkscreen Dell logo
Notebook Compatibility: Fits most laptops with screen sizes up to 15.6" (Max laptop dimension: 380mm x 260mm x 25mm)
Manufacturer Warranty: 3-year warranty
Protect your laptop when you’re on-the-go
Slip your 15-inch laptop into the durable and water-resistant Dell Essential Sleeve 15 (ES1520V) for reliable protection wherever your busy day takes you. Designed to fit snugly and securely, the neoprene sleeve, with soft, brushed Nylex interior lining, protects your laptop against spills, bumps and scratches.
Convenient to use
Easy-access, zip-top opening with smooth-gliding double zippers let you easily slide your laptop into place and tuck it under your arm as you head out to your next appointment.
Lightweight and easy to carry
Tuck your laptop into the lightweight, neoprene sleeve and carry the sleeve on its own. Or slip your laptop into the snug-fitting sleeve and place it in your favorite bag when you head out the door.