Abstract: A directional screen includes a structure defining an opening; one or more first members attached at one end to the structure. The one or more first members configured to move between a first operational position and a second operational position. A method for treating a borehole.

Abstract: A retractable display apparatus (10) comprises a housing (12), a drum (14) journalled for rotation in the housing, a display sheet (16) wound on to the drum, and a slot (22) in the housing through which the display sheet can be unwound from the drum against the action of a return spring, wherein a flexible leader strip (28) extendable through the slot is provided for releasably attaching the display sheet to the drum (14) in an easy and convenient manner outside the housing (12). The leader strip (28) has ribs (28.2) along both longitudinal edges, one rib being engageable with the drum and the other with an undercut formation (30) secured to the display sheet (16).