1) Product Overview
The children's hat grows with the child thanks to the 3-level size expansion system (swivel buckle + removable pads). Suitable for children 6-10 years old, only need to buy once and can still be used throughout the early-late primary school period.
2️) Highlights
+ 3-level head circumference adjustment (50–52–54 cm, maximum 55 cm) with the knob or drawstring mechanism.
+ Removable pads allow to increase/decrease the space inside, creating a comfortable fit as the child grows.
+ Cost savings: parents do not need to change the hat every year, still meeting the protection standards.
3️) Standard Size & Specifications
+ Head circumference: 49–55 cm, 3 levels: 50–52–54 cm, can be expanded to 55 cm.
+ Length (forehead → nape): 24–26 cm, ensuring the nape of the neck is covered without squeezing the neck.
Width (ear → ear): 18–20 cm, keeps the shape when expanding the size.
Crown height: 13–15 cm, unchanged when expanding the size.
+ Foam pad (liner): 1.5–2.0 cm, removable pad, adjustable thickness.
Weight: 225–265 g, slightly larger than the regular version due to the expansion mechanism.
+ Brim: 23.5–4.5 cm, standard for children's lines.
4️) Materials
+ Outer Shell: Polycarbonate (PC) in-mold or ABS; UV-stable coating to prevent yellowing.
+ Impact Liner: EPS density 40–80 kg/m³; 15–30 mm thick, divided into air chambers for lightness and shock absorption.
+ Inner padding (Comfort Pads): Antibacterial moisture-wicking fabric (CoolMax/bamboo blend), removable and washable.
+ Retention & Expansion System (Retention + Expansion):
- Ratchet dial or sliding strap mechanism inside the rim.
- Removable padding for 0.5–1 cm increments each time.
- Polyacetal side-release buckle, 12–15 mm nylon strap.
5️) Expansion Mechanism
+ Principle: Inner rim is fitted with a sliding plastic ring linked to the dial. When twisted, the ring contracts/expands evenly around the head, maintaining light and evenly distributed pressure.
+ Durability: Tested for a minimum of 2,000 rotation cycles, the clamping force remains <10% reduced.
+ Safety: The locking system automatically stops at a maximum of 55 cm to avoid unfastening.
6️) Testing & Standards
+ Applicable standards: TCVN 5756:2015 or CE/EN1078.
+ Tests: Impact, Retention/Roll-off, Strap Strength, Field-of-Vision like Luminous Friend.
Additional features:
- Expansion Durability Test: Continuous rotation to test the durability of the mechanism.
- Pad Compression Test: Ensure the removable pad does not compress too much after 3 years.
7️) Lifespan & Warranty
+ Helmet: Replace after 3–5 years or immediately after a strong impact.
+ Size expansion mechanism: 1-year warranty on sliding/locking, easy maintenance (light lubrication is possible).
+ Removable pad: Lifespan ~2 years; recommended to replace with a new pad if it loses elasticity.