Below are some helpful definitions to understand more about how SummerMuff products protect your child from the sun's damaging rays.

How do SummerMuff products block the sun?

SummerMuff products use custom-made organic jersey cotton (t-shirt fabric) treated with natural minerals for all our products to block the maximum amount of dangerous UVA/UVB rays. The fabric has a sun blocking factor of 40-50+UPF. It is official UV Block tested & rated by the International UV Testing laboratories UV fabric testing.

What is UPF (Ultraviolet Protection Factor)?

UPF refers to the amount of UV rays blocked by apparel and fabrics. Some facts about UPF:

UPF measures both UVB and UVA rays.

We use SPF & UPF interchangeably when talking about SummerMuff products because we know there is confusion about the differences. UPF is the correct measurement for fabrics like those used for our products and we have the maximum UPF protections available at UPF 50 blocking up to 98% of the sun's harmful UVA and UVB rays.

UPF is a transmission test: A fabric gets exposed to a UV source that simulates the sun's rays at noon. The amount of UV rays blocked by the fabric is measured by a device called a spectrophotometer. The UPF rating refers to how much UVR is blocked. For example, a UPF 50+ blocks 97.5% of the sun's UVA and UVB rays.

What does SPF mean?

SPF is an abbreviation for Sun Protection Factor. This was developed to rate the general effectiveness of sunscreen lotions and their ability to block UVB rays when used strictly as prescribed under their directions for use (SPF ratings historically have not applied to UVA rays).

SPF rating numbers such as SPF 15, SPF 20 and SPF 30 are the more common ratings seen on sunscreen lotions. The SPF number is determined by dividing 100 by the percentage of ultraviolet radiation transmitted through the sunscreen.

For example, if a sunscreen blocks 95% of UVB rays, then 5% are transmitted, so that particular sunscreen would have a rating of SPF 20 (100 ÷ 5 = 20). A sunscreen that blocks 97% of UVB rays would have rating of SPF 30 + (100 ÷ 3 = 33).

SPF Lotions are a problem for many reasons. They have to be re-applied every two or three hours due to evaporation, washing off or wearing off. And, as everyone knows who has used chemical sunscreens, they are greasy and messy. Another significant factor is skin type and skin tone. Different types dramatically affect the effectiveness of sunscreen chemicals. These chemicals are also not recommended for use on toddlers and infants. That's yet another reason SummerMuff can protect your baby!