The ASRock DeskMini X300 is a 155 mm cube with a 120 W brick

The DeskMini X300 is a proper little cube at 155 × 155 × 80 mm, powered by an external 120 W DC adapter (19 V, 6.32 A). The compact case means you’re limited to whatever storage and RAM fit inside at build time — there’s no room to add expansion cards later.