Hard Roof and Hard Coal

Hard Roof and Hard Floor

Heat Exchange Tube and Tube Sheet

Tube in Tube Structure

Tube to Tube Sheet

Tube-in-tube

welding between heat exchanging tube and tube sheet

Tube—in—tube

(semi) hard process

3 channels hard cholecystoscope

A Good Man Is Hard to Find

a hard case

a hard nut to crack

a hard row to hoe

a hard sphere unit

Abnormal hard tissue formation in pulp

abrasion-resistent plate by hard bead welding

Acicular hard coke

acid coagulated hard cheese

acid pump of hard porcelain