This is exactly what I was looking for! I bought it to wear my pump with an evening gown and the slip was perfect! My pump wasn’t clipped anywhere odd and I didn’t have to accept a “pump lump” from clipping into shorts either. It was invisible but I still had easy access, which is what I was looking for. 10/10! I sized up, since I don’t love things extremely tight, and it was perfect for me. Snug for sure, but not uncomfortable