Shimano Altus derailleurs and shifters were made in the late 70s and early 80s. They were lower level components, comparable to today’s 105 or Tiagra. I had this group on my 1981 Schwinn Super Le Tour.
Rear derailleur
Capacity: Front differential – 13 teeth, Largest rear sprocket – 28 teeth
Weight: 262 grams
Material: light alloy/steel
Front derailleur
Capacity: 14 teeth
Weight: 122 grams
Material: light alloy/steel
Downtube Shifters
Type: friction
Weight: 85 grams
Material: light alloy/steel