The average size is about 1 m in length and very stout. Large specimens of 190 cm (75 in), weighing over 6.0 kg (13.2 lbs) and with a girth of 40 cm (16 in) have been reported. Specimens from Saudi Arabia are not as large, usually no more than 80 cm in length. Males are usually larger than females and have relatively longer tails.
The head has a less than triangular shape with a blunt and rounded snout. Still, it is much wider than the neck. The rostral scale is small. The circumorbital ring consists of 10–16 scales. Across the top of the head, there are 7–11 interocular scales. 3–4 scales separate the suboculars and the supralabials. There are 12–17 supralabials and 13–17 sublabials. The first 3–4 sublabials contact the chin shields. Often, there are two fangs on each maxilla and both can be functional.