The Sharp EL344R is a handheld calculator built around unit conversion. Forty-four metric conversions are stored in the calculator and reached through colour-coded conversion keys, so switching between imperial and metric length, weight, volume, area and temperature takes a keystroke rather than a remembered factor — useful in trades, shipping, kitchens and classrooms alike. An extra-large 10-digit display handles fraction calculation and fraction-to-decimal conversion, which suits measurement work where mixed numbers are the natural way to write a figure. A three-key memory holds a running value, and sign change and percent cover everyday arithmetic. Twin power runs it on solar energy with battery backup, so it keeps working in poor light and does not stall mid-job.

• 44 built-in metric conversions
• Colour-coded conversion keys for easy operation
• Extra-large 10-digit display with fraction calculation and conversion
• 3-key memory
• Sign change and percent keys
• Twin powered — solar with battery backup