How do you know?

Meaning, is she wearing latex or playing with a gadget in one of her pictures? If so, mention something like "I love such and such image of you in the black vinyl boots playing with the toy." She'll get the hint.  

Most ladies offer GFE/PSE and won’t have things like latex. In their case, you can expect a nice two piece bra and panty set, stockings, garder belts, teddies etc. They don’t always have the specific outfit they’re photographed in. It’s acceptable to imply that you like a type of outfit, or that you loved an outfit she was wearing in a photograph on her website. You can also ask - Do you have anything like - X? That’s all it takes. You’re not asking her to wear anything, only if she has an outfit like that. She’ll know what that means.  

Girls who have latex outfits often offer BDSM and like to play doms. Some may be open to playing a more PSE scenario for you with the dom outfits, but that’s going to be case by case. If you have P411, you can also write a little about the outfits you like, or role play scenarios in your profiles bio. I’ve done that and asked the provider to look at my request there. It’s a better way to communicate a fantasy. It’s on my profile and not sent to anyone. You’re simply asking her to visit your profile and read the bio.