The bolt circle is the notional circle that determines the position of the bolts. These fasteners are very similar to hex bolts. Bolted construction with Grade 8 bolts is used throughout. The structure is bolted to the foundation with 72 bolts, each one long. Tesla sent technicians to customers' homes to tighten the rear, inner hub flange bolts. These bolts block the retraction of the main locking bolts. The head is connected to the body by means of threading, bolts, or tie rod. Note that AN threads are different for bolts and fittings. Solenoid bolts, a type of electromechanical locking mechanism, also exist. The head bolts must be re-torqued (retightening process) regularly. Other support measures can include steel arches, rock bolts, and mesh. Diana can also manipulate lightning and create weapons out of lightning bolts. A light shines from the fell, and from that light strike bolts of lightning. The floor was a corrugated sheetmetal insert, secured with 26 recessed bolts. Some of these homes were connected to their foundations with anchor bolts and foundation straps.