Felco #2 pruners. I bought these 16 years ago when I worked landscaping in college. Comes with it's own servicing tool and you can buy each individual part from the manufacturer, IF
FELCO Model 9 Secateurs (Large, Left-Handed) : Amazon.co.uk: Garden
FELCO Model 9 Secateurs (Large, Left-Handed)
Greenman Premium 9" Heavy Duty Large Pruner Secateurs Very Sharp Bypass Action for Larger Hands