Small and Light is one of Amazon’s specific shipping programs on the UK and DE marketplaces. In order to qualify, you have to have sold 10 articles in the previous month.
Next, a separate SKU (and maybe also FNSKU/EAN) will be created for the qualified products.
S&L benefits are reduced shipping costs and simpler packaging.
On the downside, PAN EU is not an option due to separate stock and shipping centers.
If you want to do S&L yourself, you have to pay 2€ in shipping costs, 1.70€ with the Central Europe Program (CEP). With SPACEGOATS, you pay 2.20€ (1.70€ plus the usual 0.50€ unit cost).