Snorkels are useful backups for surface swims and double up for snorkeling between dives.
FF Snorkeling Mask
Single Lens Mask
X-Vision Ultra, Liquid Skin Mask
Mares One Vision Mask
Children's size scuba mask
Low Volume Freediving Mask
Silicon comfort mask strap, keep one in your Save-a-dive kit.
Simple is best... small light weight and almost unbreakable. Put one in your Save-a-dive kit.