Features: Allergy free natural essential oil. Water resistant design. One size fits all, adjustable to fit all cats. Non-allergic and odorless, safe and eco-friendly. High efficiency and last up to 8 months. Well packaged in a aluminum storage case. For repelling fleas, ticks, lice, larvae, mosquitoes, etc. Specifications: Material: Rubber+aluminum Suitable for: Neck circumference sizes within 30cm Item Size: 35 * 1 * 0.3cm Item Weight: 11g Package Weight: 30g Package Size: 8.6 * 8.6 * 2.6cm / 3.39 * 3.39 * 1.02in Package List: 1 * Collar 1 * Case