Bought a DP F8 from him, he told me it developed a leak between the time he tested it before putting it up for sale and shortly before I purchased it. He tried to fix it but didn't have the materials to take care of it. Still he told me where he thought it was leaking from and sure enough that was the spot. After fixing it, the marker worked just like he stated it would. I would definately do business with him again, especially since he managed to get it to me from San Diego, CA to Topeka, KS in three days.