Sally Hansen Double Duty Strengthening Base & Top Coat is here. The product has been a long time favorite for it's many function, here are the details from www.sallyhansen.com:
All-in-one patented strengthening base and top coat works double time...for double protection. As a base coat, Double Duty moisturizes and hydrates nails with Panthenol. As a top coat, Double Duty protects with Nylon.
I've used it many times and it coated the nails and then gives the colors some added shine and perfection so it'll last longer on the nails. I even use it to prolonged it's life, so when the shine seems 'reducing' from the polish, I re-apply Double Duty for a somewhat-like-new again looking nails.
It's a simple, can't go wrong product from Sally Hansen that gives the nails protection (since 'care' is their main idea), shines and stronger nails at once.
Tips from me: If you're really into nails, please do let your nails 'rest' once in a while (like a week of every month) so the nails has time to breathe and get some sun shine too.