см. тж. высоко~
• The supporting structure must have a secure foundation.
• The concrete structure must be built on sound rock.
• A rigidly built saw-frame ...
• The housing is covered with vulcanized rubber, leather-like in appearance, but much more durable .
• High-strength steels.
• The transmitter is a robust ( or rugged ) unit.
• The weld must be sound and free from cracks.
• At speeds and altitudes where only the staunchest materials will serve ...
• This material is mechanically strong .
• The relays are ruggedly built .
• Such systems must be rugged enough to withstand shocks.
• Sturdy latches, substantial handles ...
• A stiff construction can be obtained by ...