Possible Clues:

• Cm. tenths
• Ruler divisions: Abbr
• Picture-texting standard letters
• Units marked on a wooden stick: Abbr
• Phone-text-with-pictures letters
• A foot has 304.8 (Abbr.)
• Ruler divs.
• A foot has 305 of these: Abbr.
• Sml. metric units
• Music degrees