1. SQ80D is with 900W motor while SQ80D1 is with 750W motor, both induction type.
2. SQ80D uses REX compatible type threading die head. It is quick-open type and you can control the thread length by yourself. SQ80D1 uses 100 type threading die head. It uses sliding block to control the length of threads and it is fixed.
It mainly depends on your using hobbies.
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