Hi guys,I was mainly doing body weight workout and has a bit of experience on bodybuilding.I recently bought an adjustable dumbbell at home which cannot be dropped.So when I was doing bench press,at 25kg each hand I could do 10-12 rep and lift them back,but at 27kg I felt the weight is heavy,and it’s a struggle to lift them back up after I finish the set yet I couldn’t dropped them as it would spoil my dumbbell.Is it more of technique issue as I have not much experience bench pressing or is it that if I do it enough I would be able to lift them back up soon?Thanks…

if you can DB BP 10-12 reps easily at 25kg, seems pretty weird you're struggling at 27kg

have you weigh them just to be sure?

Yea,it’s only 2kg different but lifting up after the reps is more difficult for 27kg then 25kg

10-12reps is endurance training to grow stronger muscle and tendon
If yr muscles big enough can try add more weight 6-8rep with 5mins rest continue work again

Yr body doesn't adapt or the muscle too too small27Kg that's why feel heavy

a matter of getting used to the bench pressing movement using db's. Your shoulders and core need to act as stabilizers for the weight and if it is not used to the db pressing movement it will be difficult at first. Plant your feet firm on the ground and follow the proper technique and ROM. Also maybe put mats on the floor as it is dangerous if you cant drop your dbs on the floor in the event you cant handle the weight due to failure (it happens). Safety first.
https://www.youtube.com/watch?v=v8y8dQZMJXw

get some mats, weights/plates are meant to be dropped/abused - they don't lose their efficiency due to cosmetic damage.

so get thick mats to protect your floor, as you also need to be able to drop your DB on a dime for safety purposes, you wouldn't want to mess up your shoulder/wrists just because you're trying to "baby" the weights.

Also, something is really wrong if you could 10-12rep 25kg, but couldn't even 1-5 rep a 27kg. Usually if someone could rep til 10+ it would mean the weight is already too light and it's time to add weight until you could max out at 9-10reps again. Progressive overload.

My problem is I got a knockoff bowflex adjustable dumbbell and it states that it cannot be dropped no matter.I can lift 12 reps 27kg each hand for 5 sets,the difference is that I can lift it back up on the 25kg no need to drop,but the 27kg I can lift it back up too but struggle