bell stratus mips reflective bike helmet women& 39 Ghost Women's Cycling - Matte/Gloss Hi-Viz - Large From long climbs to finishing sprints Bell Stratus Mips Helmet -

When you pack it with a laptop or books, you can feel some space between the bag and your back

one example: Patagonia uses recycled polyester in Black Hole backpacks (material claim) [43] Patagonias Black Hole Pack 25L uses recycled polyester and has a TPU film laminate (feature/spec) [43] Patagonia Black Hole Pack 32L includes Fair Trade Certified sewn label (factory/social certification) [44] Fjllrvens Knken uses Vinylon F (a durable, lightweight fabric) per product description [45] The Knken 16L packs capacity is 16 liters (product spec) [45] The Knken Art capacity is 7L (product spec) [46] Ospreys Talon 22 has a capacity of 22 liters per product specs [47] Ospreys Tempest 20 has a capacity of 20 liters per product specs [48] Thules Accent 23L has a 23 liter capacity per product specs [49] Thules Subterra 34L has a 34 liter capacity per product specs [50] Nomatics Travel Pack has 32L capacity per product specs [51] Decathlons Quechua Forclaz 35L trekking backpack capacity is 35 liters (product spec) [52] Decathlons MH500 35L lists rain cover included (feature) [52] Adidas Classic 3-stripes backpack capacity is 21.5 L (product spec) [53] LEGOs Brick backpack volume is 18 L (product spec) [54] Nikes Brasilia backpack capacity is 40L per product description/spec [55] Targus CitySmart backpack includes a 15.6-inch laptop compatibility spec (feature) [56] Dells Premier backpack lists up to 15.6-inch laptop compatibility (feature) [57] REIs Co-op Ground Control backpack (example) lists 20L capacity (product spec) [58] REIs Co-op Trail 40 (example) lists 40L capacity (product spec) [59] Patagonia Black Hole packs use matte TPU film laminate (material/feature) [43] Many backpacks specify water-resistant fabrics

A Google effort would likely provide complete information on all letter codes

A decent amount

It looks like Arai specifically designed the shock-liner segments to allow for thin-arm eye-glasses to be easily fitted and comfortably worn

Because its used while seated, it removes balance concerns entirely