The links have gone in my saddle bag in case they are ever needed. I cant review the product but the order was handled with no problems.
Shimano 11 Speed Quick Link SM-CN900 Pack of 2
You'll need a tool.
Snap into place nicely, but need a good amount of force. Can get away with applying the rear break and pushing down on the pedal (link positioned in upper chain), but will need specific pliers to remove. I would recommend the park ones.