Backhoe loaders are very common and can be used for a wide variety of tasks: construction, small demolitions, light transportation of building materials, powering building equipment, digging holes/excavation, landscaping, breaking asphalt, and paving roads. Often, the backhoe bucket can also be replaced with powered attachments such as a breaker, grapple, auger, or a stump grinder. Enhanced articulation of attachments can be achieved with intermediate attachments such as the tiltrotator. Many backhoes feature quick coupler (quick-attach) mounting systems and auxiliary hydraulic circuits for simplified attachment mounting, increasing the machine's utilization on the job site. Some loader buckets have a retractable bottom or "clamshell", enabling it to empty its load more quickly and efficiently. Retractable-bottom loader buckets are also often used for grading and scraping. The front assembly may be a removable attachment or permanently mounted.