The two strings with the blue and yellow silk are Artones,,which were one of the best strings that you could buy. Billy Linneman at the Opry swore by them,,I have a few of them and they are some of the best guts I have ever encountered,,The red gut is a Red O Ray which were made by the E.O Mario co,which made strings under the Labella name as well,, they also had like 4 other lines of strings,, all were about the same,Nutones,Sweetones,etc. The plain gut is anyones guess,, its had a knot tied in it so it could be anything,, most older guts either had a loop tied in the end or the gut itself made the loop, so it could be a old string that broke and was retied,,. Kent