Two firms have launched portable pumps to help breastfeeding mums collect their milk on the move.
Women who use breast pumps often apply them several times a day and for periods of about 20 minutes or more.
However, generally they have to be plugged into a power socket and the pump mechanism is noisy.
Both Willow and the Freemie Liberty pump are designed to be worn more unobtrusively – placed inside a woman’s bra.
Unlike traditional pumps, they are powered by rechargeable batteries and are very quiet.
They are both on show at the CES tech trade fair in Las Vegas.
“Mums have a lot of stress, they have to plug into a wall, often they are isolated in a tiny room and they have to step out of life,” said Willow chief executive Naomi Kelman.
“One teacher told us she had to stop and go in a supply closet to pump.”
Willow won an award for its device at CES in 2017, since when the pump has been available to buy as a beta trial, but it is now launching onto the market, retailing in the US for $479 (£354).
It has faced some criticism online from those who have tried it out, including comments that the bags, which hold 4oz (118ml) of milk, are too small.
A spokeswoman said that in future “bag options” of different sizes would be available, and added that the pump can be paused while the smaller bag is changed over.
The Freemie Liberty pump comes with 8oz bags.
It is the first portable product from Dao Health, which launched its first wearable pump in 2013 after 10 years of development. Until now its devices have required a power socket.
It has a “sleep” setting that switches it off after a certain amount of time should the user want to doze off while pumping – although many women find that difficult.
Co-founder Dr Stella Dao, an emergency doctor, and her husband Dan Garbez came up with the idea when their twin babies were born prematurely.
“They were in the neonatal intensive care unit, my wife realised she was having to use her breast pump 10 or 12 times a day which required her to take off her clothes, and do it for 20 to 30 minutes at a time,” said Mr Garbez.
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“The point she impressed upon me is that her job situation is difficult and demanding but lots of women around the world have difficult and demanding jobs and they can’t just drop what they’re doing and use a breast pump.”
Willow comes with an accompanying app – currently only for iPhones – which women can use to track their milk production.
The Freemie Liberty, in contrast, does not but is compatible with other apps on the market, said Mr Garbez.
It retails for $300 in the US and is also included in some health insurance plans.
Tech analyst Carolina Milanesi from Creative Strategies said it was encouraging to see products on the market that offered women more flexibility.
“In the busy life we are living and in the attempt for women to better balance career and family I sure welcome better solutions to empower me not to have to prioritise one over the other,” she said.