The MX5500 keyboard is arguably the best keyboard for people in engineering and design fields due to one feature. The built in "Smart Calculator" that automatically copies results to the clipboard. I am a mechanical engineer, and dozens if not hundreds of times a day I use the built in calculator to do some simple math like converting units or adding lengths, and then paste the result into my design software. It saves me so much time and hassle. Please reintroduce this feature on one of your keyboard models before my MX5500 kicks the bucket. Thank you!