This catalog supersedes all other Instruments, Inc. documentation. A separate price sheet is available upon request. Please contact the factory. Units for export are designed to operate from a 50 or 60 Hz main AC and are usually built as specials. Their prices are higher than the standard domestic prices listed. Some units are already specified for 50 / 60 Hz and are export ready at only a slight extra charge. Some units may not be available for export to all countries. Please contact the factory concerning your needs. Specifications and prices are subject to change without notice.