1. Basic Parameters Capacity:
Common specifications: 100ml / 120ml / 150ml / 180ml / 200ml (30-50ml are less common, mostly travel-sized)
The actual filling volume should reserve 10%-15% space to ensure the foaming effect. Material:
Bottle body: PET (transparent / frosted), PP (more chemical-resistant) or HDPE (environmentally friendly thick-walled).
Pump head system: PP plastic (core components need to be corrosion-resistant, such as stainless steel spring + silicone sealing ring).
Syringe: PE or silicone (needs to match the viscosity of the liquid).
Size reference (example for 100ml):
Diameter: approximately 45-55mm (bottom)
Height: approximately 140-180mm (including pump head)

2. Key Parameters of Foaming Pump Head
Foaming Principle:
The facial cleanser and air are mixed through the double-layer pump core (gas-liquid mixing chamber), and fine foam is squeezed out.
Foam Density: Approximately 0.05 - 0.1 g/ml (affected by the viscosity of the liquid and the formula).
Pump Head Type:
Pressing type: Commonly 1-2 presses to produce foam (each foam output volume is approximately 0.3 - 0.6 ml).
Locking Design: Rotatable locking for prevention of accidental pressing (essential for travel size).
Foam Fineness: Determined by the mesh size of the filter (usually 20 - 50 mesh).
Operating Force:
Pressing Force: Approximately 2 - 5 N (must be user-friendly, easy for children to operate).
Pressing Stroke: 15 - 25 mm.

3. Performance Requirements
Sealing:
No leakage when inverted or under pressure (0.3 - 0.5 MPa).
Chemical Resistance:
Capable of withstanding common ingredients in facial cleansers (such as surfactants, glycerin, alcohol, etc.).
Durability:
Pump head life ≥ 1000 presses (no jamming, no leakage).

4. Appearance and Customization
Bottle shape: Straight, narrow waistline, flat design (for space saving), etc.
Color: Transparent (revealing contents), milky white (for light blocking), or custom color.
Printing: Screen printing, heat transfer printing, label application (must be water and wear-resistant). Accessories: Dust cover, anti-theft ring, gasket, etc.