Williams will bring 'almost a first-race upgrade' to Formula 1 pre-season testing in Bahrain.

Williams launched its new car for the upcoming season last week, having already completed a shakedown at Silverstone with drivers George Russell and Nicholas Latifi in late February.

The team is aiming to bounce back from a difficult period that has seen it finish last in the constructors' championship in each of the past three seasons.

The FW43B has undergone a number of changes internally despite the freeze in the technical regulations, allowing the team to get down to the weight limit.

Although Williams is placing a lot of focus on developing its 2022 car, team principal Simon Roberts revealed that it has a number of different parts to try this week in Bahrain through testing.

"We're now trying to design and develop the car for '22, which is an enormous change," Roberts said.

"It's a completely new set of regulations with no carryover. But there's also some opportunity because we have done some work on this car.

"Interestingly, we've got a few options that we're taking to Bahrain for the test. It's kind like of almost a first-race upgrade, which is really cool and we're really excited about that.

"We've actually got an upgrade plan through the year, but it's gong to be pretty modest, and I expect like other teams, we'll be looking very careful at how we put our resource on that."

Asked directly about the upgrade that would be taken to pre-season testing, Roberts coyly said that that it meant the team was "either ahead of schedule or we can't make our minds up on what we really want!"

He added: "We've got some options, so we're going with a range of parts that we'll get on the car.

"It's great – it's a nice position to be in. Both drivers will get to try both options and we've got enough parts around us to convert stock for the race.

"So yeah, it could be first race upgrade, which would be a nice place to be, depending on which one we choose."

Roberts explained how the carry-over in the technical regulations from 2020 to 2021 ensured the team could go over every single part of the car and find improvements where possible.

"We've taken the time and we've been around everything we can possibly touch to try and save weight," he explained.

"We've rebalanced all the coolers on the car and re-optimised everything we could, Again, it's not the normal rush into it because we know the car, we've been racing it for 17 races last year, so we've got tons of data. It's allowed the engineers to really go to a level that we don't always get the chance to do.

"We've saved quite a good bit of weight on it. The thing is easier to build, it goes together really nicely. Hopefully it'll be more reliable, and that's certainly the intent.

"All those little things you don't get a chance to fix, we've been able to sort out. The target is to find some performance, be more reliable, and start to move our way up."