A-szcxtop(TM) 10pcs Mini Compass 20mm Diameter Liquid Filled Plastic Button Compass for Hiking Camping Outdoor Sports OD size: 20mm (approximately size of a penny) Liquid filled, works under sub-freezing temperatures. Easy to read compass dial sealed with clear acrylic top and black plastic base. Grooved edge for easy carrying with a lanyard. Each compass weight only 0.08oz.