Heat-Resistant Double-Walled 304 Steel: Constructed from food-grade 304 stainless steel with double-walled insulation. This design retains heat excellent for your coffee while keeping the exterior cool to the touch, preventing burns during espresso extraction. Stackable & Portable Design: Features a smart nestable design for space-saving storage in travel bags or cabinets. With a compact profile (62mmx60mm) and ultra-lightweight build (75g), it is ideal for both home use and outdoor adventures like camping. Brand-Coordinated Dual-Color Style: This mixed set includes two distinct cups-one Teal and one Grey-finished to perfectly match the OutIn aesthetic. It creates a cohesive, stylish look for your setup, whether you are at home or on the go. Sharing & Machine Compatibility: A 2-cup set designed for sharing moments. The precise 75ml capacity is calibrated to match the extraction output of the OutIn Nano & Mino, as well as most standard espresso machines.