A halogenated dideoxy sugar derivative, having the following general structure I wherein X is halogen,R1 and R2 are H or Br; R3 and R4 are OH or OAc. A sensor detects a transparent light reflective coating on a transparent sheet and defines a sample profile. A second insulating layer covers the first insulating layer. A plastic quick-release coupling device acts as a clasp system for selectively and releasably coupling a strap first end to a strap second end.