Universal adjustable base with secure twistlock: expandable cup holder base adjusts to most standard round car cup holders. Twist the and bottom in opposite directions to lock it firmly in place. Compatible with cup holder openings 66–100 mm in diameter. Fits large and unusual drinkware: extrawide opening and Ushaped side cutout accommodate extralarge tumblers, big water bottles, insulated bottles with handles, and handled mugs that don't fit standard holders. Builtin slim phone and smallitem slot: integrated 2in1 organizer features a narrow slot sized for smartphones and other flat items such as cards, keys, or coins, keeping them upright and within easy reach while freeing up the center console. Stable, rattle performance: nonslip base pad plus secure rubber grips hold the insert steady to minimize noise and movement on rough roads. Designed to keep drinks upright and reduce spills and distractions. Simple installation and removal: quick twistandlock action secures the unit without tools and removes just as easily for cleaning or transfer between vehicles. Thoughtful, compact design: expands only as much as needed to fill the cup holder, so it stays snug without bulk and keeps your console organized. Practical use scenarios: Daily commute: keep a large travel mug and your phone close at hand without wobble or spill during stopandgo traffic. Road trip or family drive: fit multiple sizes of bottles and handled mugs in different vehicles while keeping small items like toll cards and coins stored safely. Rideshare or delivery drivers: provide a stable holder for varied drinkware and a secure place for a smartphone or essential cards. What it solves: Eliminates the frustration of drinks that won't fit or topple in standard holders. Reduces spills, rattles, and distractions from loose items. Keeps your vehicle interior tidy by combining drink and slimitem storage in one compact insert. Key specifications: Fits cup holder base diameters: 66–100 mm Expandable twistlock mechanism Ushaped side opening for handled mugs Nonslip base pad and rubber grips Integrated slim slot for phone and flat items Compatible with most standard round car cup holders and designed for repeated use without fuss.