This listing is to add an Interior D-ring to your SI13. The D-ring will match the hardware you previously selected. Carabiner not included. 
 
Watch how we make the SI13
 
SI15 Add-on: Wider for Larger Laptops $119
Laptop Sleeve $35
Dual Front Pocket $45
Full Wrap Straps $55
Back Newspaperpocket/Luggage handle Slipover $45
Dual Gusset with Document Pocket $150
Upgrade to Hand-stitching $195
Interior D-ring for key attachment $12
Pen loops (3) $22