What is meant by S1P? S1P models expand on the features of ST safety shoes to include puncture-resistant soles. Here you can find an overview the S1P features. Related articles What safety classes are there and how do they differ? What are professional shoes and what is meant by O1 and O2? How do I find the right shoes? What is standard EN ISO 20345? Where can I find orthopaedic inserts for my work shoes?