The Delta Sigma pulse-echo ultrasonic time-of-flight (TOF) measurement device; measures, displays, stores and transfers bolt load and elongation data in a new, single purpose unit. The Delta Sigma uses a rugged, sealed colour touch screen for all operator I/O. The screen uses proven medical touch panel hardware. The measurement system is a hybrid technique, using the best of both analogue and digital signal processing techniques for fast signal acquisition and precise single shot TOF measurement. All data is logically presented on a 4.3” colour, resistive touch screen, bare fingers not required. Data and digital signal traces are stored for later display and transfer. The unit has automatic temperature compensation through an included magnetic temperature probe. The novel memory system has a secure sector for all bolt data and a “public” sector for data transfer via USB to computer. The unit is powered by proven Panasonic Li-Ion batteries or through dual charger inputs: fast charge standard external 9V supply or the waterproof micro USB connector from any standard 5V USB device, battery pack or power supply.