Crux RK40 The RK40 is a bigger version of the RK30. The only other difference aside from the volume of the sack itself is that the RK40 features internal sleeves that give you the option of inserting two tubular titanium frame stays (available separately). These make the pack more comfortable if you are lugging heavy loads (e.g. a big rack with a couple of ropes). This is the new 2020 model and features a new removable front/side compression system. Features: Roll-top design Fantastically light Welded construction throughout Completely waterproof Kevlar fabric Accessory pocket at rear Removable webbing front/side side compression system Oversized back haul loop – easy to grab and clip Top compression strap Two ice-axe holders Removable padded hip-belt 38 mm webbing waist-belt Technical Specifcations: Capacity: 2440 cu. in. / 40 litres Weight: 995 g Fabric: 40% Kevlar / 60 % Cordura, 7 oz/yd² / 240 g/m² Frame: Option for two 0.275in / 7.00 mm Ø tubular titanium frame-stays (not supplied with product) Sizes: Regular (up to 180 cm / 5\'11\") and long. Colours: Black and Red