You are buying 25 feet of 3/8" ..BLACK/NEON YELLOW  spiral,  expandable sleeving

manufactured by  TECHFLEX   PET - FLEXO  BRAND

relaxed it is 3/16" (min. diam) ---- expanded it is 5/8"  (max. diam.) 

1/8"  1/4"  3/8"  and  1/2"  are available

......It is a P.E.T. PRODUCT..................