The best I've found so far is NSI Secrets Gel. It's a great soak off LED enhancement gel, but I have found it's brilliant for repairs underneath gel polish. If I have a client with a break, I put NSI Secrets base on the nail, followed by a coat or two of their clear builder gel and then apply the gel polish directly on top. Most times, the repair lasts for two/three weeks. For clients with really weak nails it's great underneath gel polish. The only problem is that it takes longer to remove.