1. Sun Protection Factor (SPF): SPF measures the level of protection the sunscreen provides against UVB rays, which are primarily responsible for causing sunburn. An SPF of 40 indicates high protection against sunburn.
2. Broad Spectrum: A good sunblock cream typically offers broad-spectrum protection, meaning it protects against both UVA and UVB rays. UVA rays can cause premature aging and skin damage.
3. Water Resistance: Some sunscreens are water-resistant, which means they provide protection even when you sweat or swim.
4. Non-Comedogenic: Sunblock creams that are non-comedogenic are less likely to clog pores and cause acne or breakouts, making them suitable for various skin types.
5. Moisturizing Properties: Many sunblock creams also contain moisturizing ingredients to keep the skin hydrated and prevent dryness caused by sun exposure.
6. Dermatologically Tested: Products that are dermatologically tested are usually considered safe for use on the skin and are less likely to cause irritation or allergic reactions.

Remember, it's essential to follow the instructions for application provided by the manufacturer, reapplying as directed, especially after swimming, sweating, or towel drying. Additionally, it's a good idea to perform a patch test before using any new skincare product, especially if you have sensitive skin or allergies.