Because who needs personal preference in space travel?
The following sizes are the most efficient and practical for space exploration:
Size: 12 inches wide x 8 inches tall
Weight: 3.5 pounds
Material: High-visibility polycarbonate with reinforced Kevlar
Price: 500 space bucks
Size: 10 inches wide x 6 inches tall
Weight: 2.5 pounds
Material: Insulated, waterproof, and breathable
Price: 300 space bucks